Marco Vargas-Ortiz, 26, of Redwood City was arrested at the scene, in the 1200 block of Sevier Avenue, by Menlo Park police officers with the Narcotics Enforcement Team. He was booked him into San Mateo County jail.
No narcotics were involved — narcotics officers sometimes work on code-enforcement complaints.
In 2003, Mr. Vargas-Ortiz and two other suspects were arrested in connection with the sexual assault of a victim under 14. Mr. Vargas-Ortiz pleaded no contest to charges he committed lewd and lascivious acts with the child, according to the San Mateo County District Attorney's Office.
Mr. Vargas-Ortiz had been sentenced to a three-year suspended prison sentence with the provision he serve nine months in county jail, according to the district attorney's office.
The defendant never served his sentence, police said.
Officers who responded to the code-violation complaint said they observed an "illegal structure" in the rear yard of the site. The structure was "an add-on to the existing residence that had not been approved by the city with permits and is drawing electricity from main house," Detective Soares said. "It presented a fire hazard."
Police said they found several occupants inside, including Mr. Vargas-Ortiz. "We contacted two male adults and some younger children," Detective Soares said. "There were three bedrooms inside a small dwelling."
While on the premises, officers said they found and confiscated a pistol-grip assault shotgun but are unsure to whom it belongs. "It's not registered to anybody," Detective Soares said.
No arrests have been made in connection with the weapon or the illegal structure, Detective Soares said.
There are no immediate plans to evict the residents of the dwelling, he said. Police are working with homeowners to rectify the violation and are giving them a grace period to comply with the necessary permit.
Bay City News Service contributed to this report.