A City of Tonawanda man already behind bars as a predatory sex offender has admitted to more sex crimes involving children.

Donald C. Filer, 52, pleaded guilty this week to two counts of predatory sexual assault against a child, first-degree sexual abuse, and two counts of endangering the welfare of a child, according to the Erie County District Attorney’s Office.

Filer admitted raping and sodomizing a 10-year-old girl in 2007 and sexually abusing a 5-year-old the same year, the District Attorney’s Office said.

The charges carry a maximum prison sentence of 25 years to life. He is scheduled to be sentenced by Erie County Judge Thomas P. Franczyk on Feb. 7.

Filer is currently serving a sentence of 32 years to life at a state prison in Auburn for his 2008 conviction in Niagara County for predatory sexual assault against a child and three other felonies. That case involved one of the children he admitted to abusing in his Erie County plea.