A Napa High School girl’s soccer coach was arrested early Sunday after a student reported he had sent her a text message with a photo of his genitals and propositioned her for sex.

Julian Vargas, 29, was taken into custody after Napa police officers served a warrant and interviewed him at his house at 12:30 a.m., several hours after the 16-year-old girl received the photo and reported the incident Saturday afternoon.

Police also put the victim under an emergency protective order.

The girl had contacted police at about 2 p.m. saying her junior varsity coach had been propositioning her for sex since Tuesday and sent the explicit photo Saturday, according to police.

The victim also said she believed there might be other girls Vargas was contacting “with the same intent,” police said.

Vargas was booked into Napa County Jail on suspicion of “contacting a minor with the intent to commit a felony, harmful matter sent the intent to seduce a minor.”

Police have asked for anyone with information regarding additional victims or similar crimes related to Vargas to call Detective Pat Wilson at (707) 257-9338.

Jill Tucker is a San Francisco Chronicle staff writer. E-mail: jtucker@sfchronicle.com Twitter: @jilltucker