Sonoma County prosecutors filed 54 criminal charges against a Rohnert Park man Friday in what they say shows a vast and sophisticated fraud scheme perpetrated against perhaps dozens of victims throughout Northern California over the past seven months.

Mohannad Halaweh, 19, faces up to 18 years in prison after another 46 charges were added Friday in an updated criminal complaint. He previously faced eight charges.

The new charges accuse Halaweh of manufacturing credit cards at his home, using computer software to steal others’ financial identities and living a lavish life of fast cars and luxury rentals homes on the fake credit.

Halaweh was arrested June 4 in Sonoma County while driving an orange $240,000 McLaren sports car he is alleged to have rented with a fake credit card. The sleek luxury car had been reported stolen earlier that day by a South Bay car rental agency.

Since then, police from several Northern California police agencies have combed through Halaweh’s phones and computers, unearthing significant incriminating evidence, prosecutor Scott Jamar said.

In Sonoma County Superior Court, Jamar on Friday presented Judge Dana Simonds with an amended complaint against Halaweh, outlining the new charges.

Halaweh, a former star basketball player at Analy High School, remains jailed on $1 million bail.

His lawyer, William Du Bois of Pleasanton, acknowledged the new filing ramps up the case against his client.

“It’s really a lengthy document,” he said. Previously, he had characterized Halaweh’s behavior as a “youthful indiscretion.”

“It’s a rather substantial indiscretion, beyond a casual indiscretion,” he acknowledged Friday after the addition of nearly four dozen new charges.

Those include that Halaweh had a home credit-card manufacturing system and a cache of personal information stored on his computer and phones that could have been used to make fraudulent credit cards in other people’s names.

He is alleged to have rented two luxury homes, including a $12 million mansion in Sonoma County, using fraudulent credit cards.

“He would throw ridiculously massive parties with underage drinkers there,” Jamar said.

The new charges include fraud, forgery, credit card fraud in half a dozen counties from Humboldt to Santa Clara and thefts from several stores using the fake cards.

There are nearly two dozen victims identified, including Safeway and individuals whose personal financial information was found in Halaweh’s possession, Jamar said.

None of the individuals whose information was used to make forged credit cards was aware of what was being done in their name until contacted by their credit card issuers, Jamar said.

A second man arrested in the McClaren with Halaweh, Nhimia Kahsay, 19, of Santa Rosa, is also implicated in some of the new charges, Jamar said. Kahsay was arrested in connection with a Crescent City fraud.

Jamar said Halaweh stole about $150,000 worth of gift cards from Safeway stores by using fake credit cards to purchase them.

The men had been under investigation by a multi-agency law enforcement team for about two months before their June 4 arrest in connection with the sports car. The Northern California Computer Crimes Task Force began investigating in early April when Safeway’s loss prevention department contacted them.

They discovered that two men had been buying dozens of gift cards, often pre-paid Visa cards, at grocery stores up and down the North Coast. The large sums raised red flags for Safeway.

Often, they would buy several thousand dollars worth at a time.

“Sometimes they would buy $3,000 worth, then come back again later in the day and do it again,” Jamar said.

Once converted to the cards, the funds were essentially as untraceable as cash.

Video surveillance from a Crescent City store helped identify the men, police said. Kahsay likely will be charged with auto theft and possessing stolen property, Jamar said.

A hearing is set for Aug. 1, when Halaweh is expected to enter a plea.

Halaweh earlier pleaded guilty to a felony count of forgery for using a fake Visa card to purchase $10,000 worth of laptops and iPhones from a Berkeley Apple store.

You can reach Staff Writer Lori A. Carter at 762-7297 or lori.carter@pressdemocrat.com. On Twitter @loriacarter.