PORTLAND, Ore. (KOIN) — There are more than 4,000 known sex offenders living in Multnomah County and nearly 30% are non-compliant with registration requirements.

That’s why the Multnomah County Sheriff’s Office, Oregon State Police and US Marshals Service did compliance checks for several weeks in August and September as part of Operation Oregon Shield.

Officials checked in with 384 sex offenders, including 50 level 3 offenders. They made 51 criminal prosecution referrals, 11 warnings and 8 arrests for violations and active warrants. 

“Missions like these focus resources on ensuring compliance, investigating those found to be non-compliant, and keeping our community safe by holding sex offenders accountable with mandated registration requirements,” the sheriff’s office said in a press release. “One of the U.S. Marshals Service’s responsibilities is to work with state and local law enforcement agencies on sex offender investigations and operations.”

The sheriff’s office said they do these compliance checks not only to old offenders accountable, but to keep neighborhoods safe and communicate important information.