Bill Murphy’s remarks about the officers drew a standing ovation at the funeral of 25-year-old Freddie Gray.
Mr Gray died on 19 April, days after his encounter with police. The 2,500-capacity New Shiloh Baptist church was filled with mourners, many of whom filed past Mr Gray’s coffin before the service began.
Mr Gray was black while the race of the officers involved has not been disclosed. His death came amid a national debate about the deaths of black men at the hands of police after a spate of incidents.
“This is our moment to get at truth. This is our moment to get it right,” Mr Murphy said.
While the funeral was under way, police said in a news release that the department had received a “credible threat” that three notoriously violent gangs are now working together to “take out” law enforcement officers.
Mr Gray’s death has heightened tensions between residents and the police, with weekend protests at times turning violent.
A small group of mourners started lining up about two hours ahead of yesterday’s funeral. As they began filing into the church, the white coffin containing Mr Gray’s body was opened, flanked by floral arrangements. A rope was placed in front of the coffin to prevent people getting too close. One person used a mobile phone to take a photo of the body.
Placed atop Mr Gray’s body was a white pillow holding a picture of him. A projector aimed at two screens on the walls showed the words “Black Lives Matter & All Lives Matter.”
Erica Garner, 24, the daughter of Eric Garner, who died in New York police custody, attended the funeral.
She said she came after seeing video of Mr Gray’s arrest, which she said reminded her of her father’s shouts that he could not breathe when he was being arrested on a city street.
“It’s like there is no accountability, no justice,” she said. “It’s like we’re back in the fifties, back in the Martin Luther King days. When is our day to be free going to come?”
Mr Gray’s death has prompted near-daily demonstrations. He was arrested one week before he died when officers chased him through a West Baltimore neighbourhood and dragged him into a police van.
Police said Mr Gray was arrested after he made eye contact with officers and ran away. Officers held him down, handcuffed him and loaded him into the van. While inside, he became irate and leg cuffs were put on him, police have said.
Mr Gray asked for medical help several times, beginning before he was placed in the van. After a 30-minute ride that included three stops, paramedics were called.
Authorities have not explained how or when Mr Gray’s spine was injured.