An armored car company is withholding for now a $100,000 reward from an informant who led police to a Santa Rosa man suspected of stealing nearly $1 million last year during a heist at its offices.

Prosecutors will have to win a conviction against the man being held in Sonoma County jail and police will have to recover a portion of the money before Garda Cash Logistics pays any tipster, the company said.

"At this point it's premature," said Joe Gavaghan, a spokesman for the company with eight Northern California branches. "A determination about the reward won't be made until the entire process is played out."

Monico Dominguez, 39, pleaded not guilty Tuesday to being among a group of masked men who stormed the warehouse on Northpoint Parkway in Santa Rosa last August with assault rifles, tied up several employees and made off with bags of cash.

Dominguez is also charged with plotting an even bigger heist at the same location earlier this month with two other suspects. His younger brother, Juan Dominguez, 26, and Shawn Geernaert, 33, both of Santa Rosa, are also in custody.

The three were arrested Aug. 7, one day after the Dominguez brothers and an unidentified informant allegedly donned tactical clothing and body armor and drove to the Garda warehouse, according to charging documents.

Some local attorneys have wondered if the informant was an accomplice who decided to turn in the others to collect the reward. Prosecutors and police have declined to discuss details, citing the ongoing investigation.

The criminal complaint says Monico Dominguez solicited the informant's help to rob Garda and they drove the route to be traveled after the robbery.

The theft was expected to involve up to $3 million and was described in court as "unusual in its historic magnitude."

At some point, the informant went to the FBI.

It is unclear if police are still looking for other suspects who may have been involved in the 2011 robbery.

On Tuesday, the three men appeared in court in blue jail uniforms with more than a dozen family members and friends watching from the audience. Juan Dominguez is accused of planning to drive a stolen armored car with his brother to a southwest Santa Rosa cabinet shop owned by Geernaert.

All three face potential life prison sentences if convicted. They have all pleaded not guilty.

A preliminary hearing will be set on Sept. 17.

Meanwhile, Garda officials said they were pleased that suspects were behind bars. Gavaghan said the Santa Rosa operation is one of about three in the Bay Area charged with transporting money between banks and businesses. He declined to say how much money was handled each year, citing security concerns.

The company will consult with police to determine if anyone was instrumental in solving the case, he said.

"We'll use that to determine the allocation of the reward," he said.

You can reach Staff Writer Paul Payne at 568-5312 or