PHOENIX -- A former military intelligence analyst is behind bars on identity theft charges, but not before he terrorized his victims, authorities said.

Dominic Barnhill, who received nine honors when he was in the military, stole more than 100 identities, and kept detailed records on each of his victims with stolen mail, credit reports, credit cards and, in some cases, driver's licenses, said Detective Jose Garcia with the Maricopa County Sheriff's Office.

"He was bold," Garcia said. "He basically learns who he owes money to out of your credit report, and he uses that to stay away from things that will make people suspicious."

Surveillance footage captured Barnhill buying everyday items at a Tempe Target.

"He said, 'I go to the same places they go, at the same time they go, on the same days they go, and buy the same items so when the victims see the statement they see the same items they buy,'" Garcia said.

For victims Rebecca and Robert, who asked their last names not be used, the ordeal started with a ransom note.

"By the time you get this," the e-mail, sent from Robert's own account, started, "you will start to break the horizon on the scope for which I've delved into your complete existence. Listen carefully … I just need 10 days."

Someone had hacked into Robert's e-mail, bank accounts and credit cards, the couple said.

"It was like a chess match," Robert said. "Back-and-forth -- passwords, mailboxes, credit cards. One credit card would be closed, and he would immediately get another credit card number."

When the couple notified the sheriff's office, the phone rang.

"The phone call comes into our home and caller ID shows it's my cell phone," Robert said. "It's a computer-altered voice and it says, 'I told you all I needed was 10 days.' He said, '10 days was all I needed and now I'm going to F you up.'"

Robert logged into his e-mail account a short time later, but the thief had deleted "every single e-mail in my account, in my inbox, my outbox, saved mail -- everything except for his ransom note for me from me," he said.

Over the next few days, the couple realized the extent of the damage. The stranger opened 15 credit card accounts, had their mail forwarded and continued to harass them with by cell phone and text message.

Around the same time, Postal Inspector Miranda Garcia said she started getting complaints from customers experiencing mail theft.

For three months, she tracked Barnhill as he forwarded his victims' mail to empty homes, and it was under her watch that he made the mistake that led to his arrest.

"It was a credit card I was investigating," Garcia said. "He had some work done on his vehicle."

According to Jose Garcia, the way Barnhill tracked his victims was anything but ordinary.

"He would tell me some of the stuff he did from a computer standpoint -- I just didn't even know that stuff was possible," Garcia said. "He used every little bit of knowledge he had to get what he wanted."

Lt. Col. Phil Johnson said Barnhill could have acquired the skills for his plan from the military.

"He (seems to be) very conscientious," Johnson said. "He's a smart guy. He knows how to react when the pressures are on."

Apparently, when Barnhill returned from Iraq, he claimed he had post-traumatic stress disorder, and he started using methamphetamine before becoming an identity thief, Jose Garcia said.

"This guy did a lot of damage to a lot of people," Miranda Garcia said.

As for the victims, Robert said, "The six days of Hell we went through is probably going to take six months to clean up."