A Boulder middle school teacher has been arrested on sexual assault and child abuse charges. According to a message that went out to Manhattan Middle School families and staff Thursday, math teacher Dan Greenberg has been arrested on a felony charge of sexual assault on a child by a person in a position of trust and misdemeanor charges of child abuse and harassment. Former principal John Riggs faces a misdemeanor charge of failure to report, the message said. More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.