Richard Hastings, 37, was arrested at about 8:15 a.m. on Aug. 21 after he was arrested in his car on Monument Boulevard near Ramona Drive, according to police.
Concord police had initiated an investigation earlier this month into an alleged relationship between Hastings and a 15-year-old juvenile.
Investigators eventually developed enough information to arrest Hastings on suspicion of lewd and lascivious acts with a child, sodomy with a child under 16 years old and contributing to the delinquency of a minor, police said.
Hastings was booked into jail and later posted bail and was released, according to police.
Investigators today presented the case for review to the Contra Costa County District Attorney's Office, which will determine whether to file charges against Hastings, police said.
Hastings has been suspended without pay with the San Francisco Police Department, police spokeswoman Officer Tracy Turner said.
Concord police are continuing to investigate the case. Anyone with information is asked to call Detective Renee Williams at (925) 603-5856 or the department's tip line at (925) 603-5836.