A manhunt is under way for a 23-year-old Napa man suspected of robbing a string of banks in Sonoma, Lake, Marin and San Mateo counties.

The Lake County Sheriff's Office obtained a warrant to arrest Joshua James Metoxen, who they suspect robbed Tri Counties Bank in Middletown on Mar. 7 and Westamerica Bank, also in Middletown, on Feb. 27.

The detectives also identified Metoxen as a suspect in at least eight unsolved bank robberies in Sonoma, Marin and San Mateo Counties.

"We're 100 percent certain it's the same guy," said a deputy from the Lake County Sheriff's Office, who did not release his name because he's not authorized to speak with the press.

"Mill Valley was the last bank we believe he robbed. We're not sure where he's staying; otherwise he'd be in custudy."

Deputies in Marin County reported that a bank robber caught on tape in Mill Valley on Wednesday afternoon, who matched a similar description to Metoxen, may have been associated with recent bank robberies in Santa Rosa, Rohnert Park and Novato, according to a news release from the Marin County Sheriff's Office.

The Mill Valley holdup occurred at a Westamerica Bank on 1222 Redwood Highway, bringing Marin County Sheriff's deputies to the branch. Bank employees said the suspect walked in, handed a teller a note demanding money, and was given an undisclosed sum before he left, the news release said. No injuries or weapons were reported.

The suspect was last reported seen Wednesday in a mid-2000's tan Honda traveling southbound on Redwood Highway, Marin County Sheriff's deputies said. He was described as a white man in his late 20s with a large build and facial hair under his bottom lip. At that time, he was wearing a black sweatshirt, tan shorts, a red and black 49ers hat and sunglasses.

In the Lake County bank robberies, the suspect was driving a white Toyota, the deputy from Lake County said.

A multi-agency manhunt is under way. Metoxen is considered armed and dangerous and should not be approached, Lake County deputies warned.

A dispatcher at Sonoma County Sherrif's Office said deputies are on the lookout, but she had no further information about the suspect or the agency's involvement in the search.

If Metoxen is caught, bail would be set at $750,000, according to the warrant obtained by the Lake County Sheriff's Office.

"I would imagine that once we get him in custody, it's going to be one of those things where he's tried in several different counties," the Lake County deputy said.

The Lake County Sheriff's Office Major Crimes Unit, led by Lieutenant Brian Kenner and Detective Sergeant Corey Paulich, conducted the investigation, said Lake County Sheriff Frank Rivero in a statement.

"Without their efforts, this case would have gone cold and the outside agency cases would have remained cold," Rivero said.

Anyone with information is asked to call the Lake County Sheriff's Office at (707) 263-2690 or the Marin County Sheriff's Office at (415) 479-2311. To remain anonymous and possibly become eligible for reward cash, call Bay Area Crime Stoppers at (800) 222-TIPS.

You can reach Staff Writer Cathy Bussewitz at 521-5276 or cathy.bussewitz @pressdemocrat.com.