Hollywood actor Chris Pratt, who will be next seen in his upcoming thriller, `Mercy`, has shared his experience of filming with the Los Angeles Police Department (LAPD). He also shed light on the most difficult part of working on the film, and how he prepared for his new film, reports `People` magazine. In the film, he stars as an Los Angeles detective who has limited time to uncover the truth about his wife`s death after being blamed for her murder.

As per `People` magazine, the actor revealed that the most difficult part of working on `Mercy` came while he was spending time with law enforcement officers to gain a deeper understanding of his character. "I had an opportunity to work with the Los Angeles Police Department, and their homicide division and so I was able to go down and talk to those guys."