According to ABC affiliate KXTV, neighbors near the standoff think it may be connected to the murder of a Hells Angel member at a funeral in San Jose last week.
Police have not released details about the standoff, KXTV reports.
Following at least one television news report, Stockton police spokesman Pete Smith confirmed that San Jose police were serving a warrant, but would not say what the warrant was for, or provide any details.
San Jose police spokesman Jason Dwyer declined to comment on the report.
Steve Tausen, a member of the Hells Angels motorcycle club, was attending the funeral of a fellow member when he was guned down Oct. 15 in San Jose. Police believe a 39-year-old member is responsible for Tausen's death.
Police said they believe the crime scene at the funeral had been tampered with as they could find no evidence of last Saturday's shooting.
Investigators had originally believed that Steve Ruiz, the suspect thought to have shot and killed Tausen, might have been killed by members of the motorcycle gang, but said Friday they had determined he was still alive.
Authorities say Christel Trujillo may be travelling with Ruiz.
The Associated Press contributed to this report.