By Rick Sallinger

DOUGLAS COUNTY, Colo. (CBS4) – The gunman who killed a Douglas County Sheriff’s Deputy and wounded several others was contacted at least six times by the Lone Tree Colorado Police Department in the two years preceding the shooting.

Lone Tree police first came to the Riehl home June 9, 2016. They reported Matthew Riehl was involved in a fight with his father who did not press charges.

(credit: CBS)

Eight months later the eventual gunman was cited for careless driving in a traffic accident.

(credit: CBS)

Police returned to the family home in June of last year on a mental health check. Police talked to Matthew through a closed door for 14 minutes in which he insisted he was not a threat to himself or others.

(credit: CBS)

Two months later, Riehl reported to police that his mother and brother made a suicide pact and were a danger to the community.

When police responded they determined that was not true and Matthew had moved to Rawlins, Wyoming.

CBS4’s Rick Sallinger interviews Mike Samp. (credit: CBS)

It was after that he began posting threats regarding the University of Wyoming Law School.

Chief of Police for UW Mike Swam says they tried to track Riehl down and learned he was back in Colorado.

“We eventually made contact with the Lone Tree Police Department in relation to a traffic stop they had conducted on Matt Riehl,” said Swam.

(credit: CBS)

It turned out Lone Tree had given Riehl a speeding ticket. Riehl obtained the body camera video and posted it with abusive comments.

“Nazi-style SS guard Lone Tree Colorado” Riehl said.

Lone Tree police also indicated Riehl sent harrasssing emails to the department.

Riehl worked at a Walmart in Highlands Ranch until he suddenly quit.

It wasn’t until Sunday’s shooting when he reappeared on the law enforcement’s radar.

CBS4’s Rick Sallinger is a Peabody award winning reporter who has been with the station more than two decades doing hard news and investigative reporting. Follow him on Twitter @ricksallinger.