CHICAGO (CBS) — The Lake County Major Crimes Task Force has determined police officers in Lake Station, Indiana, were justified when they shot and killed an elderly man who pointed a shotgun at them, and a report sheds some light on what appeared to have been a “suicide by cop.”

The task force’s report on the shooting death of 84-year-old John Laco on Tuesday said associates described Laco as an angry man who suffered from depression.

On Tuesday, witnesses called 911 after seeing Laco hold a shotgun aloft, and fire a shot in the air in the parking lot shared by the Lake Station municipal complex and public library. When three police officers arrived, they spotted the barrel of a shotgun hanging out the driver’s window of Laco’s car. When police ordered him to drop the gun, he allegedly got out of the car and pointed it at the officers, who shot and killed him.

The report said Laco frequently made negative comments about the Lake Station mayor, and how the city was trying to force him to demolish his fire-damaged home.

Laco had been moving from one friend’s home to another since the Feb. 10 fire, when other Lake Station police officers saved his life.

The night before the shooting, Laco was supposed to appear at Lake Station City Hall, to give a progress report on the demolition, but he didn’t show up.

That same night, someone showed up outside Mayor Keith Soderquist’s home, and a neighbor heard a gunshot, then saw a vehicle – which appeared to be Laco’s sport utility vehicle – speeding away from the scene. Soderquist was not home at the time.

The task force said a shotgun shell found outside Soderquist’s house was consistent with one from the scene of Laco’s fatal confrontation with police on Tuesday.

The report also said a search of Laco’s belongings found evidence he had been stalking a former police chief, along with a note providing instructions for family members in the event of his death.