A 19-year-old man was arrested Monday when Mountain View police discovered that the driver was allegedly in a relationship with a child under the age of 14.

The suspect was first contacted by Mountain View police during a traffic stop on May 11, when he was pulled over for having multiple vehicle violations.

“As soon as our officer approached the driver, he noticed the man appeared nervous,” a police statement said.

The officer saw that a young girl was also in the car, and sensed that something wasn’t right, according to the statement.

“During the course of his investigation, he learned that the girl, who was not yet a teenager, and the man, who is an adult, were allegedly in a relationship,” police said.

The 19-year-old Sunnyvale resident was detained and arrested on May 29 on a warrant following a review by the Santa Clara County District Attorney’s Office, police said. He was arrested on suspicion of lewd or lascivious acts with a child under the age of 14, and booked into the Santa Clara County Jail.

“The girl was returned to her home in Mountain View following the car stop on May 11,” police added.