The trial of Montreal police homicide detective Mario Lambert continued Tuesday, with Lambert questioned on allegations he provided confidential information to criminals.

The 20-year veteran is accused of logging in to the police central database and typing in licence plate numbers to obtain addresses and other information, which he allegedly provided to outsiders, and potentially to criminal organizations.

Access to the police database requires an officer to enter his or her badge number, and criminal charges are often laid against anyone caught misusing the tool.

A Surete du Quebec investigation alleged he retrieved information about a half-dozen cases unrelated to his own investigations and communicated some sensitive information to a known criminal.

Lambert was arrested in the fall of 2009 in connection with the allegations.

Witnesses called to the stand in Lambert's trial have included internal affairs investigators who testified against the detective. The investigators said they interrogated Lambert for hours, but used to drilling suspects, the veteran detective was insusceptible to interrogation techniques.

Lambert's trial will last up to two weeks, during which time the detective has been suspended without pay.

Lambert is considered one of the top officers in the Montreal police homicide department, assigned to numerous murder cases and high-profile organized crime investigations.