The Detective (2007 film)

The Detective is a 2007 Hong Kong neonoir mystery thriller film directed by Oxide Pang, and starring Aaron Kwok as a private investigator hired to track down a missing young woman who may be linked to a series of murders in Thailand. The film was followed by a sequel, The Detective 2, which was released in 2011.

Knowing that Sum, the lady in the picture, is a frequent visitor of a store where the picture was shot, Tam tried to get hints of her whereabouts from the store keepers. He was told to find through her mahjong playmates. Tam started with Ming, but when he arrived at Mings home, he found Ming was hanging at the living room.As Tam continued to search for other mahjong playmates of Sum, he was shocked to find each of them murdered every time he was about to be in contact with them. He discovered a halfburnt photo at one of the scenes. Tam realized the suspicions behind the deaths and decided that he had to protect the next target of the invisible murderer. The photo was the only clue for Tam to uncover the case. ........

Source: Wikipedia