A Watertown man was arrested Tuesday for the second time this year on allegations that he molested a boy.

Carlos W. Mansilla, 26, of 418 Arsenal St., is charged by state police with first-degree criminal sex act and endangering the welfare of a child. He is accused of subjecting a 9-year-old boy to sexual contact during 1998, police said.

He awaits grand jury action after being released without bail by Brownville Town Justice Richard M. Parker.

Watertown police charged Mansilla in April with first-degree criminal sex act in an incident alleged to have occurred March 17 at a city residence. The victim in the city case was listed as a 12-year-old boy.

Information on the status of the city case was not available Tuesday afternoon.