CHICAGO (CBS) — William Calloway, the community activist credited with pressuring authorities to release the Laquan McDonald shooting video, choked back tears as he tried to put into words what Friday’s guilty verdict  against Jason Van Dyke meant.

“It was only because of God that we got justice,” Calloway told reporters about an hour after Van Dyke was found guilty of second degree murder and aggravated battery. “We did a lot of praying, a lot of work. We were peaceful.”

He said the conviction should be a “source of inspiration for not just Chicago but all cities across America to let them know that excessive force and unlawful and unjustified and unreasonable use of force by police officers will not be tolerated.”

Video showed Van Dyke shooting McDonald, armed with a knife, 16 times.

Calloway, is among those credited with pressuring authorities to release the tape. He joined forces with freelance journalist, Brandon Smith, who filed a Freedom of Information Act (FOIA) requesting all video from that night.

Calloway called on Mayor Emanuel to resign and was highly critical of black alderman for what he said was their lack of support in the case.