The family of a black man shot and killed by San Francisco police in an incident captured on video is demanding a federal civil rights investigation, their attorney announced on Monday. John Burris, who is representing Mario Woods' family, said San Francisco police have engaged in a pattern of excessive force and illegal stops and detentions of Latinos and African-Americans that warrants a probe by the US Department of Justice. He cited two other deadly police shootings and recently uncovered racist text messages between officers. Burris said he also asked the DOJ on Jan. 6 to investigate the five officers who shot Woods for possible criminal charges after they acted like a "firing squad." "This is a golden opportunity for everyone to take a look at the San Francisco Police Department," he said at a news conference joined by Woods' mother, Gwendolyn Woods, and members of the NAACP civil rights group. Police were responding to a stabbing report in the city's gritty Bayview neighborhood when they encountered and surrounded Mario Woods, 26. Five officers shot and killed him after he appeared to raise an 8-inch (20-centimeter) knife and approach an officer, according to police. Woods' family has disputed that account and filed a lawsuit against the department. Burris said on Monday that Woods was not "aggressively fighting" the officers, who should have backed away. Video clips of the incident have circulated widely online, sparking protests and calls for Police Chief Greg Suhr's resignation. San Francisco police didn't immediately return a call for comment. DOJ spokeswoman Dena Iverson said she was checking to see whether Burris' request had been received. Suhr has said the department is investigating the shooting and its "use-of-force" policies and procedures and has called on the police commission to provide the department with stun guns. Burris said an independent, outside group should investigate the department's policies, not Suhr, who he said has "ratified" all police shootings. "It seems to us he has a bias already," Burris said. Gwendolyn Woods also spoke at the news conference, saying through tears that she wonders whether her son experienced pain or thought about where she was when he was shot. "I hope he didn't suffer," she said.