Four Toronto police officers are expected to appear in court in May after being accused of providing false testimony in another courtroom.

The officers are facing obstruction of justice and perjury charges in connection with a January 2014 traffic stop in Toronto's Chinatown neighbourhood. The group faces a total of 21 charges relating to the incident.

The charges are related to the case of Nguyen Son Tran, who was arrested after allegedly driving through a red light. He was accused of drug possession and drug trafficking after officers found heroin inside the car.

However, a judge dismissed the charges against Tran, saying the drugs were not admissible due to an "unreasonable search and seizure."

The judge also said the officers' testimony was inconsistent.

Judge Edward Morgan wrote: "The false creation of a pretext to search the defendant's vehicle, combined with collusive fabrication of a story by the two lead officers as to why they came to assist in the traffic stop of the defendant, certainly amounts to egregiously wrong conduct."

Const. Jeffrey Tout, Const. Benjamin Elliot, Det. Const. Fraser Douglas and Const. Michael Taylor have all been charged in the case. After a brief hearing in court, the case was put off until May 9.

With a report from CTV Toronto's Janice Golding