A convicted child molester with a knack for eluding authorities was sentenced to 155 years for sexually abusing two boys, including a prepubescent youngster whom he was living with in the U.S. Virgin Islands, officials said Thursday.

Authorities say Gary Lee Brown, 54, who lived in St. Croix under a fake name to avoid the islands' registry of sex offenders, convinced the boy's troubled family that he would be a suitable caregiver, and then sexually assaulted the youngster in his home.

"This guy was a true monster," said Robert Soto of the special investigations division of the islands' Department of Justice. "I thank God these kids are getting the counseling they need to try and get past this."

Brown came to the attention of St. Croix investigators in 2007 when the U.S. Marshals Service found he was living under an assumed name and had not registered with police under the Adam Walsh Act, the federal law named after the slain 6-year-old son of "America's Most Wanted" host John Walsh.

Some 24 years earlier, a jury in Bernalillo County, New Mexico, convicted Brown of sex offenses and sentenced him to 27 years in prison. He served 18 years before being released, then was sent back to prison after moving to North Dakota and failing to register as a sex offender.

The U.S. Department of Justice said Brown moved to St. Croix shortly after his second stint in prison in 2003.

When Brown was discovered in St. Croix on May 31, 2007, detectives were shocked to find him living with one boy and regularly caring for another, younger child on weekends and school holidays. Their ages were not released.

An investigation found that Brown, who was a regular volunteer with a St. Croix youth program, regularly molested the two boys during the roughly four years he lived in St. Croix.

He was convicted in April 2008 on 20 charges including aggravated rape and unlawful sexual contact. The court also imposed a $50,000 fine and ordered that he pay restitution to each victim.

U.S. Attorney Paul Murphy said in an e-mail that "this case represents our commitment to protecting all children."

Soto, the Department of Justice official, described the investigation into Brown as "a very hard case, emotionally and spiritually."

"I thank God we were able to get this guy off the streets," Soto said.