Former Santa Rosa police officer Robert "Steve" Starling testified Tuesday that he used his law enforcement training and brief experience as a Brinks driver to stage a series of armored car heists that netted him hundreds of thousands of dollars.

Taking the witness stand for the first time in his nearly two-week trial, Starling recounted for jurors when he first realized he could get away with the robberies and how he used police voice commands and knowledge of the companies' deadly force policies to ensure no one got shot.

Also, Starling said he carried a pellet gun that resembled a firearm instead of a real gun because it wasn't traceable and he knew if he got caught it would mean less prison time.

"I wasn't going to shoot my way out," said Starling, 36, a one-time soldier with the Army's 82nd Airborne Division. "The Airsoft gun was a prop and that's all it was."

Starling is charged with four armored car robberies from 2007 to 2009 in Santa Rosa, Sebastopol and Novato. He's also charged with making fake 911 calls to divert police in Novato and during an aborted heist in Rohnert Park.

He faces about 40 years in prison if convicted of the 10-count complaint.

Starling testified he joined the Santa Rosa Police Department after leaving the Army. He served for nine months while going through the police academy and then switched to Sonoma State University, where he was a cop for nearly two years. He came back to Santa Rosa for another three years before leaving the department voluntarily in 2006, he testified.

He took a job at the Brinks armored car company, where he eventually was a driver on route No. 404 serving the Santa Rosa area. He testified he was making up to 50 stops a day and noticed security breaches.

For example, he testified guards often were kept waiting outside their truck carrying "large amounts of money" before bank employees let them in. And he knew Brinks policy prohibited the use of deadly force unless guards' lives were at stake, he testified.

He came up with a plan to take guards by surprise, grab their money bags and run off in a matter of seconds — all the time using a fake gun, he said.

And it worked. In the first heist outside an Exchange Bank on Stony Point Road in Santa Rosa, a disguised Starling said he ran at the guard with his gun drawn, yelling at the man to get down. The guard took one look at him, dropped the bag and dove over a nearby hedge, Starling said.

"You yell at someone loud enough and they are going to do what you want them to do," Starling said.

Starling picked up the bag and fled on foot. He said he opened it at a nearby Raley's grocery store and found it contained $180,000.

Starling said he was emboldened by the success. In his next robbery, he hit an armored truck outside the Bank of America in Montgomery Village that was delivering more than $400,000. Starling used an accomplice for a third robbery in Novato and a fourth in Sebastopol.

Andrew "Cooper" Esslinger, 27, was charged with being a lookout. He and Starling were arrested in August after the FBI traced cell phone calls made during the Novato robbery.

Esslinger has pleaded to lesser charges in exchange for testimony. On Tuesday, he said he had no idea Starling was using a fake gun and believed Starling would kill him if he ever told police. He also said he wore a body wire to record conversations with Starling. He faces six years in prison.

A lawyer for Starling concedes three robberies but says they were done without a real firearm. If jurors agree, that could shave years off a sentence.

Starling's testimony continues Wednesday. The case could go to the jury by Friday.