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LONE TREE, Colo. — The Lone Tree Police Department had interaction with Copper Canyon Apartments shooting suspect Matthew Riehl dating back 18 months.

The department released a timeline late Tuesday night of its various interactions with him.

June 9, 2016: Police responded to a family disturbance at a Lone Tree residence where Riehl was in an altercation with his father. Family did not press charges and Riehl left for the night.

Feb. 18, 2017: Riehl was issued a citation for careless driving for a traffic accident he was involved in.

June 8, 2017: Police conducted a welfare check at a Lone Tree residence when Riehl’s mother asked police to check on him because of concerns over his mental health.  Officers spoke to Riehl for almost 14 minutes through a closed door as he would not let them in. He stated repeatedly he was not a danger to himself or others, and officers had no probable cause or information to force the issue.  Mental health service information was provided to the suspect and his family, but they denied services offered.

Aug. 16, 2017: Riehl called in a welfare check stating that his mother and brother made a suicide pact and were a danger to the community. Officers responded to the residence and found this to be untrue. During this visit, police learned from the mother that Riehl had moved out of the house a month earlier and was staying in Rawlins, Wyoming. Because of a lack of probable cause, there were no charges filed against Riehl over this incident.

Nov. 10, 2017: A police officer issued Riehl a speeding ticket in Lone Tree that resulted in a court summons.

Nov. 14, 2017: A detective with the University of Wyoming Police Department reached out to Lone Tree police regarding Riehl and social media posts that he had made that were possibly threatening to the university.

In November, Riehl also shared posts on his social media account about a specific Lone Tree officer and a citation he had received on Nov. 10.

His behavior escalated to include harassing emails directly to Lone Tree officers.

Because Lone Tree police confirmed Riehl resided at an address in unincorporated Douglas County and his posts directly involved a Lone Tree officer, police contacted the Douglas County Sheriff’s Office to investigate, and provided all available information and reports regarding Riehl.