Nearly one year after armed and masked men pulled off a brazen robbery of an armored car company in Santa Rosa, three men were arrested on suspicion of conspiring in the heist.

Santa Rosa police took the men into custody Tuesday while making all-day raids at six homes and two businesses in and around Santa Rosa and as far afield as Cloverdale, police said.

Monico Dominguez, 39, is being held on $5 million bail at the Sonoma County Jail and faces eight felony charges, including kidnapping, robbery and conspiracy, according to arrest records.

His nephew Juan Domin-guez, 26, whose bail was set at $2 million, is being held on suspicion of conspiracy, attempted robbery and kidnapping. He also was being held in connection with an alleged probation violation stemming from a felony burglary conviction.

Officers also arrested Shawn Geernaert, 33, of Santa Rosa. He is suspected of conspiracy and possessing an assault weapon and was released from the Sonoma County Jail on Wednesday after posting a bond for his $10,000 bail.

Juan Dominguez was apprehended Tuesday in a dramatic SWAT team raid on a Cloverdale house that startled the usually quiet neighborhood, while Monico Dominguez and Geernaert, a cabinet maker, were pulled over separately while driving their cars in Santa Rosa.

None worked for Garda Armored Car Services, although detectives have not yet ruled out involvement from someone inside the company, Lt. Steve Bair said.

The late-night holdup took place Aug. 11, 2011, in a west Santa Rosa corporate center on Northpoint Parkway at an unmarked stucco office of Garda Cash Logistics, a branch of Montreal-based Garda World Security Corp.

Masked men with high-powered weapons slipped in behind an arriving armored car as it entered a gate, then disarmed two employees, tied them up and forced them to cooperate at gunpoint, police said.

They made off with a substantial amount of cash, although police and Garda officials declined to say how much.

Garda offered a $100,000 reward. At the time, police officials called the crime the most significant robbery in Santa Rosa in many years.

The investigation dragged on for nearly a year as detectives chipped away at leads. The case ramped up a week ago when "recent developments" led detectives to seek search warrants for six homes and two businesses, including the workplaces of two of the men arrested, Bair said.

On Tuesday, at least 50 Santa Rosa officers, Sonoma County sheriff's deputies and FBI agents participated in orchestrated raids. The effort began early and lasted well into the night.

In Cloverdale, officers surrounded a North Jefferson Place home. Neighbors reported the sound of repeated explosions, apparently from police concussion devices.

Juan Dominguez was detained by the sheriff's SWAT team and brought to the Santa Rosa Police Department, where he later was arrested. Five other adults were detained at the property and taken to Santa Rosa to be interviewed. They later were released.

In Santa Rosa, Monico Dominguez was arrested in his car on Sonoma Avenue near Yulupa Avenue.

Geernaert also was arrested in his car, at Hearn and Dutton avenues. Officers found an assault weapon at his home, Bair said.

A Garda spokesman Tuesday said the company has revamped its security measures at the Northpoint Parkway facility since the robbery.

The publicly traded company also provides international security details for diplomatic and private purposes in high-risk areas such as Afghanistan and Iraq.

Joe Gavaghan, a spokesman for Garda World Security Corp., said he could not comment on Tuesday's arrests.

"We are actively cooperating with police in that investigation," Gavaghan said.

A Garda security representatives has been in Santa Rosa helping police with the the investigation, Bair said.

You can reach Staff Writers Julie Johnson at 521-5220 or julie.johnson@pressdemocrat.com and Randi Rossmann at 521-5412 or randi.rossmann@pressdemocrat.com.