A Union City police officer resigned from the force on Friday, about two weeks after being convicted of a misdemeanor count of lewd or dissolute conduct in public, authorities said.

Sean Mace, 37, has been under investigation since February, when two women accused him of exposing himself in a Fremont home, said Detective Bill Veteran.

Mace, also a fitness and nutrition consultant, was invited to the residence on Feb. 11 to discuss fitness with the women, Veteran said. During the conversation, police said, Mace pulled down his pants and exposed his genitals.

The women, ages 41 and 52, asked him to leave and filed a complaint with Fremont police a few days later, Veteran said.

The Alameda County District Attorney's Office began an investigation and Mace was arrested on April 23, police said.

Phone messages left for Mace's attorney, Judy Odbert, were not returned.

Mace, a Solano County resident, entered his plea Aug. 16 at the Fremont Hall of Justice, where he was sentenced to three years of probation and ordered to pay a $800 fine, Deputy District Attorney Teresa Drenick said.

He received a one-day county jail sentence, but avoided incarceration because of time already served, according to court documents. He also was ordered to stay away from the two women, authorities said.

When the allegation surfaced in February, Union City police officials took Mace off duty and placed him on paid administrative leave, Horner said.

"Union City police commanders conducted a separate personnel investigation into the alleged misconduct while being respectful of the officer's due process and statutory protections," Horner said.

Mace joined Union City police as an officer in 2006.

Contact Chris De Benedetti at 510-353-7011. Follow him at Twitter.com/cdebenedetti.