context: Liu Siu-jian (Jet Li), a Chinese intelligence agent, is sent to Paris to help apprehend Chinese mob boss Mr. Big (Ric Young), who is involved in heroin smuggling. He meets Inspector Jean-Pierre Richard (Tchéky Karyo), a corrupt and violent French police detective, at a hotel. Richard tricks Liu into believing he is simply providing reconnaissance of a meet involving Mr. Big. The plans are changed when Mr. Big is introduced to two prostitutes, one being Jessica Kamen (Bridget Fonda), an American woman, who takes him to his room to service him. While Liu and the rest were watching through the surveillance camera, Mr. Big kicks everyone out except for the two prostitutes. While a prostitute is on top of Mr. Big, she attempts to murder him. Witnessing the events from a surveillance room, Liu rushes to stop the prostitutes. Richard enters shortly later, only to shoot Mr. Big and the prostitute with Liu's police-issue handgun, framing Liu for the murders.Realizing he has been set up, Liu manages to escape from the hotel with a surveillance tape showing Richard shooting Mr. Big. Chinese liaisons are sent to France after the events to investigate the matter, as Richard makes Liu the primary suspect. However, the liaisons do not believe the story Richard provides. Liu manages to contact one of the liaisons, in an attempt to pass on the tape to reveal the truth. Due to French police surveillance, the meet between the liaison and Liu is spotted, and the liaison is assassinated. During Liu's escape, he loses the tape in the chaos, and is forced to maintain a low profile.As he considers his situation, he meets Jessica, whose daughter was kidnapped by Richard to force her into prostitution. Liu discovers Jessica was the second prostitute at the hotel during the night of Mr. Big's murder. He realizes she can prove his innocence, but she refuses to go without her retrieving her daughter, Isabel. Liu decides the tape would provide the best evidence, and sends Jessica to Richard's office to steal the tape. Jessica manages to get the tape, so Liu and Jessica head to an orphanage where Isabel is kept. However, Richard anticipates this move after discovering Jessica has stolen the tape, and ambushes the couple at the orphanage. During their escape, Jessica is shot in the chest. Liu manages to get her to the hospital in time, and becomes driven to retrieve her daughter. Liu arrives at the police station where Richard is holding Isabel hostage, and fights his way through Richard's henchmen to his office. Once at the office, Liu rescues Isabel, getting shot by Richard in the process. To save Isabel, Liu kills Richard by sticking an acupuncture needle into the back of his neck in a forbidden location known as the "kiss of the dragon," which stimulates all the body's blood to travel to the brain to cause a painful death via a brain aneurysm. Liu survives the gunshot wound, and returns Jessica's daughter back to her mother.
question: What proof Liu have, that proves Richard as a criminal ?
answer: A surveillance tape showing Richard shooting Mr. Big