Three officers with a police service on Montreal's South Shore are under investigation over allegations they sold drugs for criminal biker gangs.

Radio-Canada has learned that the Sûreté du Québec (SQ) launched its investigation several months ago following serious allegations involving two detective sergeants and a patrol officer from the Régie intermunicipale de police Roussillon.

Roussillon is a regional municipality located just south of Montreal, in the Montérégie region.

SQ Capt. Benoit Rich…