LOCKPORT – A Niagara Falls sex offender, awaiting sentencing on three felonies, was arraigned Monday in Niagara County Court on a new indictment accusing him of a series of sex acts with an underage girl last year in the Falls.

Derrick J. Houser, 26, formerly of Cedar Avenue, is charged with second-degree criminal sexual act, two counts of third-degree criminal sexual act and single counts of third-degree rape and endangering the welfare of a child.

Assistant District Attorney Robert A. Zucco said the victim was 14 when the alleged crimes began in March 2012 and had turned 15 by the time of the last of four alleged incidents in early May.

Houser, a Level 1 sex offender, pleaded guilty March 8 to two counts of failure to register. He moved to Detroit last June without telling police and also failed to disclose his Facebook account. Those violations constituted a violation of the terms of his probation for his original offense of attempted first-degree sexual abuse in 2009, authorities said. He is scheduled for sentencing May 10 on those felonies.