Montgomery County detectives arrested Roy Andres Simmons III on charges he inappropriately touched a 10-year-old girl at a Potomac after school program in 2016. (Montgomery County police/Montgomery County police)

A former paraeducator and after-school program employee turned himself into Montgomery County police Thursday to face charges that he inappropriately touched a 10-year-old girl at a Potomac elementary school in November 2016, officials said.

County police arrested and charged Roy Andres Simmons III, 41, with one count of fourth-degree sex offense and one count of second-degree assault, officials said in a statement.

Police said Simmons, who lives in the 9500 block of Bell Vernon Place in Gaithersburg, worked for a company called "Kids Adventures," which ran a program at the victim's school, Carderock Elementary and a school official said he also worked part-time for the county in the school.

The investigation began in May, when the victim told police she was touched at an after-school event where Simmons was a group leader for the company last fall. The touching happened while the victim was separated from other students, police said.

Officials said Simmons "admitted to the inappropriate contact" during a police interview.

In a letter, school principal Jae W. Lee said that Simmons was known as "Andy" when he worked at Carderock Elementary as a part-time paraeducator for the school system and for Kids Adventures after school.

"Mr. Simmons was immediately terminated from [Montgomery County Public Schools] after allegations were shared with the school," Lee wrote. "These charges are deeply concerning and wholly unacceptable."

Detectives obtained an arrest warrant Tuesday and he turned himself in Thursday, officials said.

Police are investigating whether Simmons touched any other students. Both police and school officials urge parents of children who may have had contact with Simmons to speak with their children and to call police at 240-773-5400, if they believe their child was victimized.