July 22, 2020

Investigations and Enforcement under Hong Kong's National Security Law – "One Law, Two Systems"



On 30 June 2020, the Law of the People’s Republic of China on Safeguarding National Security (the Law) in the Hong Kong Special Administrative Region (HKSAR) took effect. The Law is annexed to Annex III of Basic Law of HKSAR (the Basic Law) as part of the national laws that applyin HKSAR and targets four categories of crimes, namely secession, subversion, terrorist activities, and collusion with a foreign country or external elements to endanger national security. For an overview of the Law, please see our previous legal update: here https://www.mayerbrown.com/en/perspectives-events/publications/2020/07/hksar-national-security-law.

The Law anticipates application under both the jurisdiction of the HKSAR and of Mainland China (the Mainland). To the extent HKSAR jurisdiction applies, various rules and guidelines including the Implementation Rules for Article 43 of the Law (the Implementation Rules) were promulgated and took effect on 7 July 2020.

This Legal Update looks at several key aspects as they apply to enforcement of the Law and the conduct of investigations.

Enforcement and Jurisdiction

The Law provides for two jurisdictions and effectively, two legal systems to be applied in its implementation. In most cases, HKSAR jurisdiction (a common law system) will apply but there are certain exceptional cases in which Mainland jurisdiction (primarily a civil law system) may apply.

Various enforcement/governance bodies and units have also been established in HKSAR, including the Committee for Safeguarding National Security of HKSAR (the Committee), the Office for Safeguarding National Security of the Central People's Government in the HKSAR (the Office) and specialized units/departments in the Hong Kong Police Force and Hong Kong Department of Justice.

HKSAR Jurisdiction under Article 40

Pursuant to Article 40 of the Law, except under the circumstances specified in Article 55 of the Law, HKSAR has jurisdiction. Further, the Law and the laws of HKSAR shall apply to procedural matters, including those related to criminal investigations, prosecutions, trials and execution of penalties1. The enforcement authorities include the Hong Kong Police Force, the Secretary for Security, the Secretary for Justice, the Commissioner of Police and, to the extent applicable, their authorized officers.

It is worth noting the default position is that no bail should be granted, unless the judge has sufficient grounds to believe that the criminal suspect or defendant will not continue to commit acts endangering national security2. Further, when the trial involves state secrets or public order, all or part of the trial will be conducted in a closed court, albeit judgment will be delivered in an open court.

Mainland Jurisdiction under Article 55

Under Article 55 of the Law, the Mainland, via the Office, its newly established enforcement agency in HKSAR, may apply its jurisdiction under three circumstances:

"(1) the case is complex due to the involvement of a foreign country or external elements, thus making it difficult for [the HKSAR government] to exercise jurisdiction over the case;

(2) a serious situation occurs where [the HKSAR government] is unable to effectively enforce this Law; or

(3) a major and imminent threat to national security has occurred."

To invoke Article 55, either the Office or the HKSAR government need to first make a request to and obtain an approval from the Central People's Government (CPG).

Further, cases under the scope of Article 55 (Article 55 cases) will be investigated by the Office, prosecuted by a prosecuting body designated by the Supreme People’s Procuratorate of the PRC and adjudicated by a court designated by the Supreme People’s Court of the PRC3.

Interpretation of the Law

The Law states that in the case of any inconsistency the Law shall prevail over Hong Kong (local) law4. As a national law and similar to the Basic Law, the Law was drafted in Chinese, and its Chinese version takes precedence over the official English version to the extent any discrepancies arise.

Further, similar to the Basic Law, the power of interpretation of the Law is vested in the Standing Committee of the National People's Congress (NPCSC)5. This is consistent with the NPCSC's general power to interpret Chinese national laws. Article 158 of the Basic Law provides that the NPCSC shall authorize the HKSAR courts to interpret on their own, in adjudicating cases on the provisions of the Basic Law that are within the limits of the autonomy of HKSAR and sets out a general procedure for requesting interpretations from the NPCSC. In contrast, the Law is silent on this aspect which may create some practical uncertainties for HKSAR courts when ambiguity arises in a case.6

Constitutional Rights

The Law specifically requires adherence to the principle of the rule of law, the presumption of innocence and protection from "double jeopardy"7 and protection of human rights, specifically including the freedom of speech, the press and publication, association, assembly and demonstration applicable to HKSAR under the Basic Law and the International Covenants on Civil and Political Rights and the International Covenants on Economic, Social and Cultural Rights.8

Investigations and Enforcement under HK Jurisdiction

For those cases under the jurisdiction of HKSAR, in addition to those under the existing laws of HKSAR, enforcement powers prescribed under Article 43 of the Law include powers to:

  • Search places for evidence;
  • Restrict suspects from leaving the HKSAR;
  • Freeze, restrain, confiscate and forfeiture property;
  • Remove published information and require service providers to provide assistance
  • Require foreign elements to provide information;
  • Intercept communication and covert surveillance; and
  • Require information and material.

We highlight the following four investigation and enforcement measures under the Implementation Rules.

Search Places for Evidence

Under the Implementation Rules, a police officer may, with a warrant, enter and search a place (including electronic devices) for evidence; inspect, examine, search, seize, remove and detain anything in the place that the officer reasonably believes to be specified evidence9 and detain any person found in the place until the place has been searched.10 The legal test for obtaining a warrant is the establishment of “reasonable grounds” for suspecting that relevant evidence is in a place.

However, the police may also carry out a search without a warrant under certain circumstances. Section 3 of Schedule 1 to the Implementation Rules provides that a warrantless search may be carried out if a police officer not below the rank of Assistant Commissioner of Police is satisfied that there are reasonable grounds for suspecting that any specified evidence is in a place and for believing that the evidence is necessary and it would not be reasonably practicable to obtain a warrant.

Similar powers are permitted in various existing Ordinances of the HKSAR11 and warrantless searches are not completely alien under the common law12.

Freeze, Restrain, Confiscate and Forfeiture Property

When the Secretary for Security has reasonable grounds to suspect that any property held by any person is offence-related property, he may by written notice direct a person not to deal with the property.13 The United Nations (Anti-Terrorism Measures) Ordinance, Cap. 575 (UNATMO) contains similar power for the Secretary for Security to freeze property by written notice if he has reasonable grounds to suspect that any property held by any person is terrorist property.

Other notable provisions under the Implementation Rules include rules for the Court to make a restraining or confiscation order14, and to oblige a person who knows or suspects that any property is offence-related property to make a disclosure to a police officer15. These appear largely in line with existing powers in the Organized and Serious Crimes Ordinance, Cap.455 (OSCO) and the UNATMO.

Interception and Covert Surveillance

Schedule 6 to the Implementation Rules authorizes the Chief Executive to approve all applications for interception of communications and covert surveillance operations for the purpose of protecting national security. Authorization is required to perform three types of interception/surveillance activities by law enforcement agencies: (1) interception, (2) Type 1 surveillance, and (3) Type 2 surveillance.

Similar provisions exist under the existing legislation, i.e., the Interception of Communications and Surveillance Ordinance, Cap 589 (the ICSO), which applies to serious crimes and public security. Under the ICSO, applications are generally made to a panel judge for authorization before law enforcement agencies may carry out interception or Type 1 surveillance. However, the head of the agency may also issue an emergency authorization for interception or Type 1 surveillance, similar to the emergency authorization under the Implementation Rules. Moreover, under the ICSO, an authorizing officer of law enforcement agencies may authorize Type 2 surveillance, similar to that under the Implementation Rules.

Furnish Information and Produce Material

Sections on furnishing information and producing material under the Implementation Rules are broadly similar to the provisions under Part II of the OCSO and Part 4A of the UNATMO. Consistent with the OCSO and the UNATMO, the Implementation Rules exclude self-incrimination as a ground for not complying with an order made thereunder but retains legal privilege as such a ground.

Under the HKSAR jurisdiction, suspects and witnesses enjoy various rights including the right to counsel, the right to remain silent and the right to be cautioned, as the case may be. However, one needs to bear in mind that such rights that are familiar in common law systems may not be guaranteed or permitted in the same way under the Mainland legal system.

Investigations and Enforcement under the Mainland Jurisdiction

Under the Law, the Criminal Procedure Law of the PRC (the CPL) and other relevant PRC laws shall apply to the procedural handling of Article 55 cases. The Law also does not preclude the Office from transferring the suspects to Mainland China for the purpose of handling Article 55 cases. Under the CPL, state security authorities (such as the Office), when handling criminal cases involving national security, shall perform the same functions as the public security authorities, including various investigation and enforcement measures such as search, sealing and seizure of physical and documentary evidence, witnesses’ interviews, interrogation of criminal suspects, detention and arrest. As such, the Public Security Organ Procedures for Handling Criminal Cases (the Procedures) may also be relevant. Without going into detail, we highlight below certain aspects one needs to bear in mind when facing investigation or enquiries by the Office.

Right to Counsel and Right to Remain Silent

A suspect has the right to retain a defence lawyer but this right can only be exercised from the day he/she first receives an inquiry from the Office or from the day a mandatory measure is taken against him/her.16 Mandatory measures include summons by warrant, detention and arrest, bail pending trial and residential surveillance.17 Generally a defence lawyer is permitted to meet the suspect within 48 hours of the lawyer's request to meet.18 However, in Article 55 cases which concern national security the defence lawyer must file a request and obtain the approval from the Office to meet with a suspect in custody.19 Under the PRC system there is no statutory rule similar to the same type of right to remain silent that exists under common law due to the overarching duty to tell the truth under traditional PRC legal principles. The CPL provides only limited scope of a right to remain silent and states that the suspects shall answer the investigators' questions truthfully, but shall have the right to refuse to answer any questions that are irrelevant to the case.20 That said, the courts would generally exclude confessions obtained through torture or other illegal methods (such as hunger or exhaustion).21

Witnesses may also engage lawyers to seek legal advice. Anyone (except physically or intellectually disabled people, minors or those who cannot express themselves accurately) who has information regarding the case is obligated to provide evidence and testimony truthfully.22

Caution needs to be exercised in selecting and engaging legal counsel in the investigation of Article 55 cases as foreign (including Hong Kong) qualified lawyers or even PRC-qualified lawyers who are Hong Kong permanent residents generally cannot represent clients in PRC criminal cases.23 Accordingly, if the investigation of Article 55 cases takes place in Hong Kong, one may consider engaging PRC-qualified practising lawyers in HKSAR who are not permanent residents of Hong Kong to assist.

Interrogation of Suspects

The investigators from the Office may, upon producing the summons and their work identification, summon a suspect to a designated place in Hong Kong (e.g., the Office) or visit his or her residence for interrogation, if an arrest or detention is considered not necessary.24 Two investigators must be present at the interrogation and for a significant crime, the investigators shall keep an audio or visual record of the interrogation process.25

Interviewing Witnesses

The investigators may, upon producing written notice of inquiry from the Office, require a witness to provide testimony at the witness's employer or residence, a place proposed by the witness, or at the Office.26

Detention and Arrest

The enforcement authorities from the Office may detain a suspect upon producing a detention warrant.27 The maximum period of detention can be up to 37 days before one is arrested, granted bail pending trial, placed under residential surveillance or released28, subject to certain exceptions discussed below.

The enforcement authorities from the Office may also arrest a person upon producing an arrest warrant.29 Generally, a suspect may not be detained under investigation for more than two months after being arrested but this period may be extended to seven months, before the Office decides to transfer the case to the people's procuratorate for prosecution.30

At the stage of prosecution, the suspect may then be detained for another period of approximately six and a half months before he/she is either prosecuted or released.31

As mentioned above, the timeline is subject to the exceptions below and the calculation starts from:

  • The date on which the information regarding the suspect's name, residential address or identity is ascertained, if a suspect refuses to truthfully disclose such information; and
  • The discovery of any additional offence if that is discovered during the investigation.

Other Key Investigation Measures

No fewer than two investigators may, upon producing a search warrant or a written decision of sealing or seizure (as the case may be), search persons or places or seal or seize any relevant documents, materials or properties. However, when an arrest or detention is made, a search may be conducted without a search warrant in case of emergency.32

The investigators may also, with a written notification to assist in inquiries or to freeze assets, inquire into or freeze the accounts, deposits, remittances, bonds, stocks, fund shares and other assets of the suspects. The relevant parties (including companies, financial institutions and individuals) shall provide assistance.


The Law is a national law to be applied in the HKSAR and as such, differs from other existing laws in the HKSAR. Article 55 cases are expected to be reserved for exceptional circumstances, but the Law does create a new system in which both the HKSAR and Mainland laws and enforcement procedures could apply, effectively rendering it a case of "One Law, Two Systems". This may inevitably result in uncertainties in the practical implementation of the Law and require careful handling by all parties concerned.

1 Article 41 of the Law.

2 Article 42 of the Law.

3 Article 56 of the Law.

4 Article 62 of the Law.

5 Article 65 of the Law.

6 A preferred view would be that Hong Kong courts should have the right to interpret the Law when adjudicating cases within their jurisdiction, by virtue of (1) the Law being annexed to Annex III of the Basic Law and becoming part of the laws of Hong Kong and (2) HK courts have the power to interpret HK laws when adjudicating cases in HK. However, Hong Kong courts' right of interpretation is subject to the ultimate power of interpretation by the NPCSC.

7 Article 5 of the Law.

8 Article 4 of the Law.

9 "Specified evidence" means anything that is or contains, or that is likely to be or contain, evidence of an offence endangering national security (Section 1 of Schedule 1 to the Implementation Rules).

10 Section 2 of Schedule 1 to the Implementation Rules.

11 For instance, the Dangerous Drugs Ordinance, Cap. 134, the Firearms and Ammunition Ordinance, Cap. 238 and the Independent Commission Against Corruption Ordinance, Cap. 204.

12 For instance, where it would not be reasonably practical to obtain a warrant in light of the risk of destruction or loss of the relevant evidence or materials.

13 Section 3 of Schedule 3 to the Implementation Rules.

14 Section 9 of Schedule 3 to the Implementation Rules.

15 Section 5 of Schedule 3 to the Implementation Rules.

16 Article 34 of the CPL.

17 Article 66 and Article 115 of the CPL.

18 Article 39(2) of the CPL and Article 50 of the Procedures.

19 Article 39 of the CPL.

20 Article 120 of the CPL.

21 The Supreme People’s Court’s 2013 Notice on Establishing and Improving Working Mechanisms for the Prevention of Miscarriages of Justice in Criminal Cases.

22 Articles 62 and 125 of the CPL.

23 Article 4 of the Measures for the Administration of Residents of Hong Kong and Macao Special Administrative Regions Holding the Legal Profession Qualification of the Mainland and Engaging in Legal Practice in the Mainland.

24 Article 119 of the CPL and Article 194 of the Procedures.

25 Article 123 of the CPL.

26 Article 124 of the CPL and Article 205 of the Procedures.

27 Article 85 of the CPL.

28 If an arrest is considered necessary for a detainee, the Office shall apply for an approval for arrest from the people's procuratorate within 3 days of detention but such period can be extended for 1 to 4 days and up to 30 days if it involves (1) offences across different cities/provinces, (2) repeated offences, or (3) committing the offences with one or more persons. A decision should be made by the people's procuratorate within 7 days of receiving the Office's application for arrest (Article 91 of the CPL).

29 The arrest must be first approved by the people's procuratorate, under Article 93 of the CPL and Article 138 of the Procedures.

30 The extension is based on the seriousness and complexity of the offence and upon approval of the procuratorate at different higher levels, under Articles 156, 158 and 159 of the CPL.

31 The people's procuratorate will make a decision of whether to prosecute within 1 month of receiving the case from the Office and such period may be extended for 15 days (Articles 172 and 175 of the CPL). The procuratorate may decide to require supplementary investigation. Supplementary investigation shall be completed by the Office within one month and be transferred to the procuratorate for re-assessment. Supplementary investigation is limited to 2 times.

32 For instance, when there is a risk of carrying weapon or explosive or a risk of destruction or transfer of evidence.

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