A man with a history of burning tents in Chicago parks was feeling "suicidal" when he ignited a mattress at a Rogers Park apartment last week and sparked a blaze that led to the death of a Chicago firefighter, Cook County prosecutors said Monday.Sheaves Slate, 27, appeared confused throughout his in itial court hearing, resting his head on a table as supporters of slain firefighter Michael Altman packed the courtroom. Slate faces charges of murder, residential arson and aggravated arson injuring a firefighter in connection to the March 16 fire at a four-flat at 1757 W. North Shore Ave.Prosecutors said Slate started the fire during a dispute with friends. He had previously lived in the building for nine months and had since been caught trespassing repeatedly, prosecutors said. The night before the fire, Slate went to his old third-floor unit and warned the new tenants that they were “going to pay" after he was told to leave, prosecutors said. He was then spotted sleeping outside and was eventually kicked out, prosecutors said. That's when he climbed back into the building through a broken basement window and returned to a boiler room where prosecutors said he’d been “illegally staying."Feeling “depressed and suicidal" about his “poor relationship with friends,” Slate used a lighter to set fire to a mattress in the room. according to prosecutors.When he realized he couldn’t control the flames, he placed a door in front of the boiler room to conceal the flames and left, prosecutors said. He never called 911 or alerted residents. A smoke alarm went off in the basement about an hour later and firefighters responded within minutes. When firefighters moved the door, it caused the ceiling to collapse, prosecutors said. Altman fell from the first floor into the basement and was engulfed in flames. Altman fell from the first floor into the basement and was engulfed in flames. Chicago firefighter Michael Altman Chicago Fire Department Altman suffered burns to 90% of his body, a police report said. He was taken to Stroger Hospital where he was pronounced dead a day later. Meanwhile, Slate boarded a bus to the Harold Washington Library where he dyed his hair from orange to brown and changed his clothes. The next day, he checked himself into a hospital for suicidal ideations. He was arrested at the hospital on a prior warrant Wednesday, according to police records. Slate admitted he “accidentally” burned tents twice before at parks on the North Side. “No one accidentally sets things on fire,” Judge Luciano Panici said Monday before ordering Slate detained.Cook County State’s Attorney Eileen O’Neill Burke applauded Panici's ruling. “We are all grieving the tragic loss of Michael Altman — a young father and dedicated firefighter who followed in his family’s footsteps to serve and protect others,” O’Neill Burke wrote in a statement. “His death is a profound loss for the Chicago Fire Department, his family and loved ones, and communities across Cook County.”Altman came from a storied Chicago Fire Department family. He was the son of a former fire battalion chief and grandson of a former department commissioner. He’d been with the department for less than two years.Slate had been arrested at least three times since July 2025, according to Cook County court records. In October, he was placed under court supervision for a year after pleading guilty to retail theft.In January, the warrant was issued after he failed to appear in court to face charges of retail theft and possession of methamphetamine and drug paraphernalia. He previously had the same list of charges dropped in another case, records show. Related Firefighter seriously hurt battling extra-alarm blaze in Rogers Park Chicago firefighter from storied CFD family dies after injury in Rogers Park blaze Man charged with murder, arson in blaze that led to death of firefighter ...read more read less