PORTLAND, Maine — A man convicted of a sex crime in Texas more than 20 years ago pleaded guilty Wednesday in U.S. District Court to failure to register as a sex offender in Maine.

Darrell Lee Roath, 42, of Scarborough has been held without bail since his arrest on the federal charge in March.

Roath was convicted in 1988 in Texas for indecency with a child, according to the complaint. At the time, that charge included sexual contact under Texas law.

He is required to register as a sex offender for life in each state in which he lives. Because Roath moved to Maine from another state in 2009 and did not register as a sex offender, he was charged with a federal crime.

Roath came to the attention of police in Dec. 14, 2011, when a Scarborough officer spoke with Roath when he saw him walking down Route 114. Because of a rash of recent residential and motor vehicle burglaries in the area, the officer asked Roath if he had seen any suspicious activity. The defendant said he had not.

The officer later checked Roath’s name in the Maine Bureau of Motor Vehicles computer system and discovered that the defendant had been a registered sex offender in California in 2006. Scarborough police arrested Roath on Dec. 15 on a state charge of failing to register as a sex offender. About two weeks later, Roath registered as a sex offender in Maine.

He was arrested on the federal charge March 12.

Roath faces up to 10 years in federal prison and a fine of up to $250,000.