3 Blind Mice (2003)

Thomas is a young computer specialist who spends most of his (spare?) time on the net. He logs regularly on Cathy's site and apparently runs a very strong - but platonic! - relationship with her: they only see each other through web cams. One day, while Thomas is connected, Cathy is murdered under his eyes. But when he calls the police to try to "do something" he realizes that he doesn't even know her real name or address. Thomas, apparently the only witness, will soon find himself involved in the investigation held by Claire, a young police officer who is also a web specialist. Together they will discover in the real world, as well as in the virtual one, very weird things ...