BROOMFIELD — A man killed by police Thursday in Broomfield's Aspen Creek subdivision long struggled with mental illness, his family said.

Kyle Miller, 21, was shot by police Thursday morning after pointing a gun at officers near the intersection of Aspen Street and Durango Avenue. The family said they warned officers that the gun was a plastic Airsoft gun.

"I did everything I could, everything I knew was right to do to try and stop it," said his mother, Cheryl Miller.

The family had called 911 early that morning because Kyle Miller had a knife and was trying to harm himself, she said. Kyle struggled with schizoaffective bipolar disorder, which was a factor in his recently losing his job as an emergency medical technician. Cheryl Miller said the disappointment caused him to hurt himself.

Broomfield Police Chief Thomas Deland said the department cannot release more information, as the investigation is ongoing.

"Legally I'm not permitted, nor are any of my staff, to comment," he said.

The Adams/Broomfield Critical Incident Team is conducting an independent investigation of the incident. The involved officers were placed on administrative leave, which is a standard policy, Deland said.

Miller said she does not bear ill will toward the officers who shot her son.

"No one goes to work in the morning wanting to shoot someone," she said.

Yet Miller said the tragic situation highlights the need for a change in how law enforcement and the general public respond to mental-illness issues. Police had come to their house several times before and were familiar with Kyle's mental-health background, she said. Her younger son, who called 911 Thursday morning, had clearly told dispatch that Kyle had a gun that was a plastic toy, not a weapon.

"The system is broken. It's just broken," she said.

She added that the family had pushed to hospitalize their son on several occasions because of self-destructive behavior, but the Boulder mental-health center had not recommended it.

Barbara Ryan, chief executive of Mental Health Partners, which serves Boulder and Broomfield counties, said she could not comment on Kyle Miller's health background because of privacy rules or even confirm that he sought treatment through MHP's services.

"We can say that we assess these kinds of situations very carefully," she said.