SACRAMENTO, Calif. -- A convicted sex offender was arrested Monday afternoon on charges he offered a 14-year-old boy $20 and motioned for him to perform a sexual favor, police said.

John Thomas, 47, was arrested in connection with the incident that took place when the teenager exited a Regional Transit train Friday morning near a gas station at 24th Avenue and Fruitridge Road, police said.

The boy ran to the Kwick Serv gas station, where he told an employee about the man and what he said.

"He told me the guy was looking at him strange," said Hakiem Bostic, who was working at the Kwick Serv gas station on Friday. "He felt that he was looking at his private parts."

Bostic caught Thomas before he could flee the scene and held him until police arrived.

"I told him, 'If you run off, I will have to whoop you,'" Bostic said.

Thomas was charged with molesting a child.

Thomas does have a prior felony and is a registered sex offender.

Police said they fear there may be other victims.

If you feel that you, or someone you know, may be a victim of Thomas, you can call 916-443-4357.