A third suspect has been arrested after allegedly helping carry out a fake police raid that netted R14.9 million in precious stones.

A woman has handed herself over to police for allegedly helping a metro cop and his accomplices pull off a fake police raid that netted R14.9m in precious stones.

This brings the number of arrests in the case to three, with two more suspects still on the run.

Independent Police Investigative Directorate (Ipid) spokesperson Lizzy Suping said the woman handed herself over at the Edenvale police station on Monday.

"The suspect will make her first appearance before the Johannesburg Magistrate's Court [on Tuesday]," Suping said.