SURRENDERED: Charged with sexual assault, U.S. Marshals say Johnnie Walker's on the run

MILWAUKEE (WITI) -- U.S. Marshals are looking for 25-year-old Johnnie Walker.

Walker is charged with two counts of first-degree sexual assault of a child.  Between June and July, U.S. Marshals say he repeatedly sexually assaulted two eleven-year-old girls on Milwaukee's north side.

Walker is listed as "non-compliant" on the Wisconsin Sex Offender Registry.  He's been a registered sex offender since 2010. U.S. Marshals say Walker could be hiding out on Milwaukee's north side.

Walker is 5'9'' and weighs 190 pounds.  His nickname is "John John."  He has a tattoo on his left forearm of "Von Von," a tattoo on his right forearm of "Chantelle," and a tattoo on his back of a tombstone and "RIP Chantelle 1967-2002."  He also has a scar on his face on his right cheek.

Anyone with information on his whereabouts should call U.S. Marshals at 414-297-3707.