WASHINGTON — The Fairfax County police are asking for the public’s help in finding a man they say showed two young girls a pornographic video on his cellphone.

Fairfax County detectives say that two girls, ages 11 and 8, were riding scooters in the 2700 block of Blocker Place, in the Falls Church area, on Sunday at about 3 p.m. when a man drove up to them and called them over. The girls didn’t approach him, but stopped, the police say; the man then held his phone out the car window.

One of the girls said she saw the adult video, police say, and both girls ran away and told an adult what had happened.

The man was described as being in his 30s, with dark, medium-length hair and a short beard, wearing a black sweater and blue jeans. He was driving a gray four-door sedan, possibly a Toyota, the police say.

If you have any information about this case, the police ask you to call them at 703-691-2131, submit a tip anonymously through Crime Solvers, text TIP187 plus your message to CRIMES (274637), or call 1-866-411-TIPS (8477).