Complices (2009)

Two detectives learn some unpleasant truths investigating the case of a young man's murder in Complices (Accomplices) (2009). After the body of handsome-but-rootless Vincent Bouvier (Cyril Descours) is discovered floating down a river, the co-ed detective team of Herve (Gilbert Melki) and Karine (Emmanuelle Devos) are assigned to the case. The relationship between the partners is fraught with sexual tension, and as they delve deeper into seemingly ideal student Vincent's decidedly Laura Palmer-esque nighttime activities and the mysterious disappearance of his best friend Rebecca (Nina Meurisse), things may just well explode. Speaking of, Nina goes fully nude for two shower scenes, an explicit oral scene, in bed with a john, and both MMF and FFM threesomes, and if that doesn't make you explode, you better check your pulse.