The criminal investigation process: police powers, arrest, detention and bail: HSC Legal Studies

What this dot point is asking

"The criminal investigation process" covers everything from the moment a crime is reported until the accused is either released on bail or held on remand. The syllabus lists police powers, reporting crime, investigating crime (gathering evidence, use of technology, search and seizure, warrants), arrest and charge, summonses and warrants, bail or remand, and detention, interrogation and the rights of suspects. The "learn to" statements ask you to discuss police powers, examine reporting and investigating, and assess the effectiveness of the criminal investigation process as a means of achieving justice.

This is one of the most heavily examined areas of Crime. The 2025 paper alone asked three multiple-choice questions on it (detention time limits, bail factors and search warrants), and the 2025 Section II Part B marking guidelines listed bail, police powers and investigating crime as content that could support an answer.

The answer

Police powers and where they come from

Police powers in NSW are mostly codified in the Law Enforcement (Powers and Responsibilities) Act 2002 (NSW) (LEPRA), which commenced in December 2005 and brought scattered statutory and common law powers into one Act. Codification improves transparency and accountability: police, courts and the public can see exactly what police may do and what safeguards apply. Some powers sit in other Acts, such as the Crimes (Forensic Procedures) Act 2000 (NSW) for DNA samples and the Surveillance Devices Act 2007 (NSW).

Police exercise wide discretion: whether to stop someone, search, arrest or charge, and whether to divert. Discretion allows flexible, sensible policing but can produce inconsistent or discriminatory outcomes. Police conduct is overseen by the Law Enforcement Conduct Commission (LECC), established in 2017, and by the courts.

Reporting crime

Most crime comes to police attention through reports from victims and witnesses, not police detection. Reporting depends on trust in police, fear of retaliation, shame, and the relationship between victim and offender. Sexual assault and domestic violence are heavily under-reported. Measures that encourage reporting include Crime Stoppers (anonymous reporting), the NSW Police Sexual Assault Reporting Option (a confidential online report that need not lead to a formal complaint), and specialist domestic violence officers. Low reporting limits the effectiveness of the whole process because police cannot investigate what they do not know about.

Investigating crime

Gathering evidence

Police interview witnesses and suspects, collect physical and forensic evidence, and use informants. Forensic procedures such as DNA samples and fingerprints are regulated by the Crimes (Forensic Procedures) Act 2000 (NSW), which sets out when consent or a court order is needed.

Use of technology

CCTV, mobile phone location data, metadata (retained by telecommunications providers under Commonwealth law since 2015), automatic number plate recognition and DNA databases have transformed investigations. Telecommunications interception requires a warrant under the Telecommunications (Interception and Access) Act 1979 (Cth). The most striking example is Operation Ironside, announced by the Australian Federal Police and the FBI in June 2021, in which an encrypted messaging app (AN0M) secretly controlled by law enforcement was distributed to organised crime figures, leading to hundreds of arrests. Technology improves detection but raises privacy concerns, which is why its use is tied to warrants and oversight.

Search and seizure

Police may stop and search a person without a warrant if they suspect on reasonable grounds that the person has stolen goods, a prohibited drug, a dangerous implement, or something used in a serious offence (LEPRA s 21); similar powers apply to vehicles (s 36). "Reasonable suspicion" was explained in R v Rondo [2001] NSWCCA 540 as more than a mere possibility but less than a belief, and based on facts that would create the suspicion in a reasonable person. Strip searches (ss 31 to 34) require the officer to suspect the search is necessary for the purposes of the search and that the seriousness and urgency make a strip search necessary, with privacy and dignity safeguards (s 32) and extra protections for children (s 33). Since December 2024 police can also use metal-detecting wands without suspicion in areas declared under the 2024 knife crime amendments.

Use of warrants

For entry to private premises police usually need a search warrant, issued under Part 5 of LEPRA by an independent authorised officer who must be satisfied there are reasonable grounds. Surveillance device and telecommunications interception warrants are issued by judges or eligible members of tribunals. Warrants are the main form of judicial oversight of intrusive investigation, which is why the 2025 HSC multiple-choice question treated lawful entry to a home as evidence of judicial oversight.

Arrest and charge, summons and warrants

Arrest without warrant

Under LEPRA s 99 (as amended in 2013), a police officer may arrest without a warrant if they suspect on reasonable grounds that the person is committing or has committed an offence, and are satisfied that arrest is reasonably necessary for a listed reason, such as stopping the offence, preventing the person fleeing, identifying them, protecting evidence or witnesses, or protecting someone's safety. In DPP v Carr [2002] NSWSC 194, Smart AJ criticised arrest for minor offences and said arrest should be a last resort. Police may use reasonable force (s 230) and must give the person their name, place of duty and the reason for the arrest (ss 201 and 202).

Charge

If there is enough evidence, police formally charge the person, which begins the court process.

Summons and Court Attendance Notices

For less serious matters, police can issue a Court Attendance Notice (the modern NSW equivalent of a summons) under the Criminal Procedure Act 1986 (NSW), requiring the person to attend court without being arrested. This protects liberty and saves police resources.

Arrest warrants

A judicial officer or authorised officer can issue a warrant for a person's arrest, for example where they have failed to attend court or cannot be found.

Detention, interrogation and the rights of suspects

At common law, police could not hold an arrested person simply to question them: in Williams v The Queen (1986) 161 CLR 278 the High Court held that an arrested person must be brought before a justice as soon as reasonably practicable. Parliament responded by authorising limited detention for investigation, now in Part 9 of LEPRA:

• Investigation period. A reasonable time, up to a maximum of 6 hours (ss 115 and 116), excluding "time out" such as waiting for a lawyer, interpreter or medical care.
• Detention warrant. An authorised officer can extend the period by up to 6 hours if satisfied the investigation is diligent and the extension reasonably necessary (s 118), giving a maximum of 12 hours.
• Caution and summary of rights. The custody manager must caution the person that they do not have to say or do anything, and give a summary of Part 9 rights (s 122).
• Communication. The person may contact a friend, relative or guardian and a lawyer, and have the lawyer present during questioning (s 123).
• Interpreter. Where the person cannot communicate adequately in English (s 128).
• Vulnerable persons. Children, Aboriginal and Torres Strait Islander people and people with impaired intellectual functioning are entitled to a support person, and police must notify the Aboriginal Legal Service through the Custody Notification Service when an Aboriginal person is detained. This service was a key recommendation of the Royal Commission into Aboriginal Deaths in Custody (1991).

The right to silence. A suspect need not answer questions (beyond giving identifying details in some situations). Section 89 of the Evidence Act 1995 (NSW) generally prevents a court drawing an unfavourable inference from silence during questioning. The s 89A exception, inserted in 2013, allows an inference for serious indictable offences where a "special caution" was given in the presence of the suspect's lawyer and the accused later relies at trial on a fact they failed to mention. It is rarely used in practice because it requires a lawyer to be present.

Safeguards on interrogation. Admissions to police about indictable offences are generally inadmissible unless electronically recorded (Criminal Procedure Act 1986 (NSW) s 281). Admissions obtained by violence or oppression are excluded (Evidence Act s 84), unreliable admissions can be excluded (s 85), and the court can reject admissions that would be unfair to use (s 90). More broadly, s 138 gives courts a discretion to exclude illegally or improperly obtained evidence.

Bail or remand

After charge, the accused is either released (with or without bail) or held on remand until the case is decided. Bail in NSW is governed by the Bail Act 2013 (NSW), which commenced in May 2014 and replaced the Bail Act 1978.

The unacceptable risk test

The bail authority (police, a magistrate or a judge) must refuse bail if there is an unacceptable risk that the accused will fail to appear, commit a serious offence, endanger the safety of victims or the community, or interfere with witnesses or evidence, and the risk cannot be managed by conditions (s 17). The matters it must consider (s 18) include the accused's background and criminal history, the strength of the prosecution case, the seriousness of the offence, the views of victims, and the likely time the accused would spend in custody if bail were refused.

Show cause

After a review by former Attorney-General John Hatzistergos, the Bail Amendment Act 2014 inserted the show cause requirement (ss 16A and 16B), in force from January 2015. For serious offences such as murder, serious sexual and drug offences and offences committed while on bail, the accused must first show why detention is not justified.

Domestic violence reforms (2024)

After the alleged murder of Molly Ticehurst in Forbes in April 2024 by a man on bail for sexual assault and stalking charges against her, Parliament passed the Bail and Other Legislation Amendment (Domestic Violence) Act 2024. It made serious intimate partner violence offences show cause offences and, from 11 October 2024, made electronic monitoring a default condition when bail is granted for those offences unless the interests of justice require otherwise (s 28B).

Youth bail (from 2024)

The Bail and Crimes Amendment Act 2024 inserted s 22C, which from 3 April 2024 prevents bail for a young person aged 14 to 17 charged with a serious break and enter or motor vehicle theft offence committed while on bail for a similar offence, unless the bail authority has a "high degree of confidence" they will not commit a serious indictable offence. It was due to expire in April 2025; in 2025 Parliament extended it, but the Legislative Council shortened the government's proposed three-year extension (to April 2028) to 1 October 2026. On 15 September 2026 the government tabled a statutory review finding the test had helped stabilise youth crime in regional NSW and introduced the Justice Legislation Amendment (Miscellaneous) Bill (No 2) 2026 to extend it again. Parliament passed the bill on 24 September 2026, extending s 22C beyond 1 October 2026. Check the exact new expiry date before your exam: this is a live reform.

Remand

Refusing bail detains a person who is presumed innocent. BOCSAR reported a record 6,650 adults on remand in March 2026, and in June 2026 remand prisoners were 46% of all adults in custody, around one-third of them held for domestic violence offences. Aboriginal adults made up 33.9% of the adult custody population. Remand disrupts employment, housing and family, and people refused bail are more likely to plead guilty. Organisations such as the Aboriginal Legal Service NSW/ACT argue the reforms fall hardest on Aboriginal people, while victims' advocates argue they save lives.

Evaluating the criminal investigation process

Use the syllabus criteria and themes:

The most important recent evidence of the gap between law and practice is Meredith v State of New South Wales, decided by Justice Yehia in the NSW Supreme Court on 30 September 2025. The lead plaintiff, in a class action for festival-goers strip searched between 2016 and 2022, was strip searched at the Splendour in the Grass festival in 2018. The Court found the search unlawful, found failures in police training and supervision that resulted in "a flagrant disregard of the rights of the plaintiff", awarded damages and found exemplary damages should be awarded for systemic failures. The State has appealed parts of the decision, and the Court of Appeal had reserved its judgment as at September 2026. It supports an argument that LEPRA's safeguards are sound on paper but were not consistently applied.

In one sentence

The NSW criminal investigation process gives police wide, codified powers to search, arrest, detain and seek bail refusal, balanced by reasonable suspicion requirements, detention limits, the right to silence, judicial oversight and exclusion of improper evidence, although recent bail reforms and failures such as unlawful strip searches show the balance is contested.

Try this

Q1. Outline the rights of a person detained by police for questioning in NSW. (4 marks)

• What the marker wants. Three or four rights with LEPRA or Evidence Act sections: time limit, caution, lawyer and family, interpreter, right to silence.

Q2. Explain how the Bail Act 2013 (NSW) attempts to balance individual rights and community safety. (6 marks)

• What the marker wants. The unacceptable risk test and conditions, s 18 matters, show cause, and a recent reform (2024 domestic violence changes or s 22C), with a link to remand statistics.

Q3. Assess the effectiveness of the criminal investigation process in achieving justice for suspects and victims. (15 marks)

• What the marker wants. A sustained judgement using LEPRA, the Evidence Act, the Bail Act, a recent case (Meredith, 2025) and BOCSAR data, with both victims' and suspects' perspectives.