A 34-year-old Alliance man was sentenced Monday to 20 months in prison by United States District Judge John M. Gerrard, for failing to register as a sex offender.

The U.S. Attorney’s office says after his release from prison, Guadalupe Luis Sanchez was required to serve a seven-year term of supervised release and be registered as a sex offender as a result of previous sex offense convictions in Boulder, Colorado.

He was last registered in Colorado in December 2010, but after multiple contacts with local police in Alliance it was determined he had been an Alliance resident from at least October 1, 2011, to May 2, 2012, without registering as a sex offender in Nebraska.