Thousands of police officers attended a funeral Thursday for a rookie NYPD officer killed in a car accident while on duty.

Officer Michael Williams, 25, was killed Sunday when a van he was traveling in with three other officers hit a concrete barrier on the Bruckner Expressway in the Bronx. He had only been on the job for eight months.

New York City Mayor Bill de Blasio gave the eulogy at the funeral and told the mourners Williams died doing what he loved. De Blasio says Williams got his passion for being a police officer from his father, who is a veteran in the Carmel Police Department.

"He's going to be remembered as a humble police officer that went out and did this job with respect," says NYPD PBA President Pat Lynch.