Yes, a police officer can prosecute a criminal matter in any court. This is the intention of the different laws on the powers of the Police to prosecute. SEE SECTION 23 POLICE ACT, CAP.19 LFN, 2004; SECTION 211(B), (C) OF THE 1999 CFRN. However, certain procedures and practices must be considered. For example, it is provided by SECTION 268(2) ACJA, 2015 that proceedings instituted by a Police Officer shall be filed in the name of the Inspector General of Police or Commissioner of Police. This means that a Police Officer though authorized to prosecute matters, it must be in the name of IGP or COP just like, a law officer in the department of the Attorney General prosecuting on behalf of the Attorney General.
Also, by virtue of Legal Practice rules, the High Court of a State is a superior court of record where practitioners are dressed with wig and gown. Since only lawyers can wear the wig and gown, it follows that only Police Officers who are lawyers and are called to the Nigerian Bar can prosecute matters at the High Court and in the name of the Inspector General of Police or the Commissioner of Police, respectively.
It is true that a Police officer’s power to institute criminal proceedings is generally limited to courts of inferior records - Magistrates’ Court, Area Courts and Customary Courts. This is because the Police lack the authority to sign the Information or Charge sheet which are used in the State High Courts by reason of the provisions of Section 341 CPA (and for Lagos State, **Section 253 of the ACJL, Lagos State, 2011)**and so cannot institute cases in the Federal and State High Courts.
Nevertheless, it has been held in the case of Olusemo V. COP (1998) 11 NWLR (Pt. 575) 547 that the Police can represent the State in Courts of superior records, subject to the constitutional authority of the Attorney General. Since this provision by virtue of Section 98 of the High Court Act, Abuja, 1990, that decision of the police having the power to operate in the High Court would be limited to the Federal Capital Territory High Court, Abuja.
The Court of Appeal actually had so held in Osahon v. FRN (2003) 16 NWLR (Pt. 845) 89 that the decision in Olusemo’s case cannot be stretched to empower a Police Officer to institute criminal proceedings in the Federal High Court, as unlike Section 98(1) of the High Court Act, Abuja, that mentioned Police Officer, Section 56(1) of the Federal High Court Act, 1990 did not include a Police Officer amongst those that may institute criminal proceedings in the Federal High Court.
Quite curiously, the Supreme Court considering the Osahon’s case in further appeal to it, as FRN v. Osahon (2006) 5 NWLR (Pt. 973) 361 included Police Officers in the list of those who can institute and prosecute a criminal case in the Federal High Court without making the kind of clear analysis the Court of Appeal made to explain its decision on the differences in the wordings of Section 98(1) of the High Court Act, Abuja, 1990, and the Section 56(1) of the Federal High Court Act, 1990.
It is hoped that before long, some more clarifications would be pronounced by the Apex Court when the opportunity offers itself