A sex offender attacked a police officer after trying to strangle someone at a home just west of Downtown Boise Monday.

Christopher J. Sullivan, 28, punched the officer after fleeing the home in the area of North 17th and West Bannock streets late Monday afternoon, Boise police said Tuesday.

Police were called to the area by the homeowner, who said Sullivan had kicked in his door. Police say Sullivan also tried to strangle someone he knew inside the home.

Backup officers helped take Sullivan into custody. The officer he's accused of punching was not seriously injured.

Sullivan was arrested on felony charges of battery on a police officer, attempted strangulation and misdemeanor counts of resisting and obstructing an officer and malicious injury to property. He also faces a felony charge of failure to register as a sex offender after officers discovered he was living in a home that wasn't listed on his state registry

Sullivan was convicted of lewd conduct with a minor in 2000 in Minidoka County, when he was 16.