Authorities had been contacted with concerns about the mental health of Matthew Riehl, 36, over a month before he shot and killed a Colorado deputy and wounded four others. But Riehl was never held for mental evaluation. After Riehl published several social media posts critical of University of Wyoming professors, the campus police chief says officers called police in Lone Tree, Colorado, in November to warn them about Riehl, suggesting his rants were indicative of mental illness. Riehl barricaded himself in an apartment Sunday morning before ambushing deputies in an attack that ended when he was killed.