In a press conference today, New York City Chief of Detectives Robert Boyce revealed that Ismaaiyl Brinsley, the suspect in the murders of NYPD Officers Rafael Ramos and Wenjian Liu, had video of a recent anti-police protest on his cell phone.

Boyce said the video, which captures a demonstration near New York City's Union Square park in the wake of the grand jury decisions in Ferguson and Staten Island, was likely captured on or around Dec. 1.

"He's just a spectator, it seems. As people are walking by, he's recording it on his cell phone. We found that down in Baltimore where he left it," Boyce said.

At the press conference, officials also played a surveillance tape of Brinsley at the Atlantic Terminal Mall in Brooklyn earlier that day.

They are asking for help in determining Brinsley's whereabouts from approximately noon ET until the time of the shootings at approximately 2:45p ET.

Watch more above.