As an American Airlines ticket agent, Micheline Johnson had easy access to other people’s credit cards — so easy, police say, she went on a half-million-dollar shopping spree while working at Mineta San Jose International Airport.

Johnson used airline customers’ credit card numbers to purchase $100 gift cards from different Safeways two or three times every day, bundling the gift cards to later buy items such as iPhone 4s and iPads from Best Buy and other stores, and then selling the items on eBay, authorities said Wednesday in a lengthy police report.

Investigators believe she and a boyfriend even posted bids to drive up the prices.

Her alleged scheme unraveled when a former boyfriend — who also worked for the airline — tipped off Safeway, which launched an investigation and called police.

The 49-year-old Concord woman, who is married to a California Highway Patrol officer, was arraigned Feb. 3 on a 66-count felony complaint charging grand theft, possession of stolen property and identity theft, according to the Santa Clara County District Attorney’s Office.

If convicted on all charges, she faces a maximum sentence of 48 years, four months in prison, according to the District Attorney’s Office. The scheme may have gone on for longer than three years and Johnson could be responsible for millions in losses, according to a police report.

The 14-page police report, written by Detective Marshall Norton of the Mountain View Police Department, did not implicate her husband, Officer Kurt Johnson, in the alleged scam. Johnson works out of the Contra Costa CHP area office.

A message left at the Johnsons’ home was not immediately returned.

Investigators believe Micheline Johnson — who worked part time — stole credit card numbers from American Airlines customers flying out of San Jose, the police report says. She was possibly working with another person to encode the credit card numbers on counterfeit cards.

While married, Johnson had at least two boyfriends and openly told co-workers about them, the police report says.

Investigators served search warrants at the home of one of Johnson’s boyfriends, who also worked at American Airlines.

The man has not been charged. Investigators determined that Johnson and the man were both recently associated with a rental cottage in Santa Clara and shared a joint bank account.

Prosecutors allege Johnson used the counterfeit credit cards to purchase gift cards from Safeway stores in California, Nevada and Washington. Safeway analysts have linked Johnson to at least 2,800 transactions using 350 credit card numbers, according to prosecutors.

Johnson would visit several Safeway stores in one day and purchase gift cards to other stores, including Chevron, Marriott, Best Buy, Shell Oil and Target, according to a police report. The District Attorney’s Office believes Johnson would use some of those gift cards to buy big-ticket electronics from different stores and then sell the items on eBay.

Investigators tracked down Johnson’s eBay/PayPal account and determined that she had sold some new, in-the-box electronics such as Apple iPhone 4s and iPads.

“That’s how she converted it into cash,” prosecutor Tom Flattery said.

Investigators believe Johnson also used the gift cards to pay off balances on her own legitimate retail store credit cards.

Johnson and her husband own a cabin in Nevada, the police report says.

The fraudulent Safeway purchases exceed $480,000, according to Flattery. The alleged thefts occurred from December 2007 through October 2010.

Investigators located 68 victims who confirmed their credit card accounts had been compromised and recalled using those cards at the American Airlines ticketing counter to pay for baggage, fees and tickets, according to the police report.

Johnson is being held on $1 million bail and is due back in court Feb. 28.

Contact Mark Gomez at 408-920-5869.