A San Mateo County jury this week convicted Guosheng Chen on three felony sex counts stemming from a Millbrae massage appointment — the second time in two years the 48-year-old has been found guilty of a sex crime, and a verdict that raises an uncomfortable question about how he was still working a massage table at all.

The conviction is a clean win for prosecutors, but the through-line runs past one defendant. Chen already carried a 2023 sexual-battery conviction when, in December 2024, a spa handed him a solo appointment with a woman whose usual therapist was out. The business where it happened — Water Lounge Spa in Millbrae — has since surfaced in a separate county sexual-battery case. And because California's massage credential is optional, there is no automatic wall between a sex-crime record and the next client on the schedule.

Chen, 48, of Hayward, was found guilty this week of forcible oral copulation, forcible sexual penetration and sexual battery, prosecutors in San Mateo County announced. He is scheduled to be sentenced Sept. 8 and is being held on $400,000 bail.

The assault dates to Dec. 22, 2024. The woman had booked a session at Water Lounge Spa in Millbrae; her regular therapist wasn't working, so the spa put Chen on the appointment. In the account prosecutors laid out, she had told him which parts of her back to stay on before he began touching her genitals and reaching beneath her underwear. She froze, walked out, drove straight to a hospital and reported what happened.

Left out of that courtroom summary is that Chen had done this before, at least in the eyes of the law. He was convicted of sexual battery in 2023, the district attorney's office says — which means that when he took the table in Millbrae a year later, a man with a sex-crime record was giving unsupervised massages to women.

Investigators never framed this as a lone incident. After arresting Chen on Jan. 2, 2025, the San Mateo County Sheriff's Office said his massage work had stretched well beyond Millbrae — into San Diego, Contra Costa and Alameda counties as well as his home county — and it publicly urged anyone else to come forward, the kind of appeal detectives make when they expect the count to grow. NBC Bay Area, relaying Bay City News, (external source, opens in a new tab) carried that work history and the call for more victims. Patch documented (external source, opens in a new tab) that Chen landed in the Maguire Correctional Facility facing several sex offenses, one of them a sexual battery on a victim described as unconscious.

The Millbrae storefront is the detail that lingers. Water Lounge Spa turns up again in an unrelated prosecution: Enli Feng, 72, of San Bruno, pleaded not guilty in May (external source, opens in a new tab) to charges involving four alleged victims. Two of the episodes prosecutors described — one in 2021, one in 2022 — allegedly happened inside that same spa, and the investigator of record on both matters is the same detective, Nick Pitts. Two defendants, one address, one phone number for tips.

Sitting over all of it is a gap in state law. California does not require a massage therapist to be licensed to work. The California Massage Therapy Council issues a statewide certificate, but it is voluntary — a hole lawmakers have flagged for years in their own sunset review of the agency (external source, opens in a new tab). For therapists who do hold the credential, state rules push CAMTC to suspend it the moment someone is charged with a sexually related offense, and to strip it on conviction. But that only bites for people who chose to opt in — and it reaches the therapist, never the spa doing the hiring.

The Dissent could not confirm whether Chen ever held a CAMTC certificate, or whether Water Lounge Spa knew his record when it scheduled him. The Sept. 8 sentencing won't resolve either. A verdict closes one file. It does nothing about the door Chen walked through twice.