An Arizona man was sentenced to 14 years in prison Friday for scamming elderly victims with fraudulent magazine subscriptions, officials said.

Raheem Oliver, 38, was charged in Alexandria, Va., federal court with stealing $640,000 from more than 350 people. Several of the victims lived in Virginia, and many were elderly or vulnerable, including at least one man on the Eastern Shore who suffered from Alzheimer’s disease, prosecutors said.

Starting in about 2013, Oliver and others working with him, including his fiancee, would call phone numbers and offer to help potential victims renew magazine subscriptions, according to court documents.

Saying he was part of magazine publishing companies, Oliver billed the victims two or three times and made unauthorized charges on their bank and credit card accounts.

During the scam, he identified subscribers who were vulnerable and demanded in threatening phone calls that they wire him thousands of dollars at a time for renewal fees and overdue subscriptions, officials said.

One of the victims, an 84-year-old with Alzheimer’s disease in Accomack County, Va., was scammed into paying more than $50,000, prosecutors said. Oliver told the victim that his renewal payments had been returned by the bank for insufficient funds.

Raheem Oliver (Arizona Department of Corrections)

If a victim declined to pay, Oliver would threaten to sue them, court documents say.

Officials said he told a Marine veteran in Alexandria that his company would take the man to court, claiming that the man owed money for more than 200 magazine subscriptions. The veteran, who is buried in Arlington National Cemetery, sent $98,000 in personal checks before his death last year.

The veteran, whose footage of World War II battles was featured in an Academy Award-winning short documentary film, was an “American hero,” prosecutors said in a court document.

“Toward the end of his long and remarkable life, [the veteran] deserved the very best this country had to offer,” the document said. “Instead, several years before his death, he had the misfortune to be targeted and victimized.”

In other cases, Oliver impersonated government officials and threatened victims with legal action, including arrest, if they didn’t make payments through mail or wire transfers, court documents say.

Using specialized software and hardware, he would make it appear as though calls were coming from local courthouses.

Prosecutors said Oliver used the stolen money to pay for a large house in Arizona, among other personal expenses. It’s unclear how the scheme was uncovered.