The family of 24-year-old Ryo Oyamada, who was struck and killed by a New York Police Department patrol car  on Feb. 21, said they have filed a notice of claim against the department and city.

"My son came to America to study English and then a police car took his life. I'm extremely distressed," his father, Tsukasa, 60, told reporters Friday at his Manhattan lawyer's office. "I want to know the truth."

The lead attorney, Jeffrey Kim, said he has begun an independent investigation and hopes the NYPD will cooperate in sharing evidence, such as surveillance videos and speed monitoring devices, in relation to Oyamada's death Thursday. He was a resident of Kagawa Prefecture.