Six months after the Sept. 11 terrorist attacks, authorities in New York and elsewhere are investigating more than 100 people for allegedly cheating charities of more than $1 million in aid intended for victims of the World Trade Center attack.

Many of the individuals falsely claimed that a loved one died in the Twin Towers attack and attempted to collect money, according to Detective Joe Cavitolo, a spokesman for the New York City police. In some cases, the relatives never existed, and in others, they still were alive, he said.

The amount of suspected fraud represents a fraction of the $1 billion that charities say they have given out in aid. But authorities say they plan to vigorously prosecute any person who used the attacks for personal gain.

In one of the largest claims, a 37-year-old New Jersey man was indicted last week by a state grand jury on charges of falsely stating that his wife was killed at the World Trade Center. He attempted to collect more than $63,000 in survivor benefits.

Mark Christopher, of Sicklerville, N.J., identified himself as Mark Palmerri, and said he had a wife, Lisa, who worked and was killed in Tower One, according to the indictment. He received two checks totaling $52,580 from the American Red Cross to cover funeral expenses, mortgage and credit card payments, and tuition for a 3-year-old son. In fact, he has no wife and no son, according to officials, who said Christopher created the Palmerris as false identities. They discovered the fraud after he filed additional claims to a federal agency, which conducted a routine check. The telephone number at Christopher's home was disconnected.

"This case represents a repugnant fraud perpetrated by an individual seeking to capitalize on the tragedy of others," Peter Harvey, director of New Jersey's Division of Criminal Justice, said in a statement.

This month, Jerome Brandl, 34, who posed as a volunteer firefighter, was sentenced in Queens to one to three years in prison after he pleaded guilty to conning the New York City Fire Department and residents out of food, lodging and money.

Roxanna Freeman-Anderson, of Mamaroneck, N.Y., was indicted in February on charges of stealing $2,000 in benefits after she falsely claimed her two sisters and brother had died in the attacks, authorities said. When a Westchester, N.Y., charity delivered the check, she was passing off four children from her neighborhood as her nieces and nephews, officials said. She is being held in the Westchester County jail and could not be reached for comment.

Authorities in Northern Virginia said they are unaware of similar allegations in connection with the Pentagon attack.

In the first weeks and months after the terrorist strikes, donations from the public flooded charities, and relief organizations struggled to provide speedy assistance to victims and their families. Many families complained that money was slow in reaching them.

"Double-checking for fraud wasn't as much a priority," said Jeanine Moss, spokeswoman for the United Way of New York City, which administers the September 11th Fund. The fund received $456 million in donations and has given out $205 million in grants to organizations for immediate relief. "The focus was to get aid to people as quickly as possible," she said.

Now that the need for emergency aid has subsided, charities say they are spending more time verifying identities and claims and following up tips from law enforcement and the public about potential fraud.

At Safe Horizon, a Manhattan-based victim assistance group that has received $74 million from the September 11th Fund, a panel formed shortly after Sept. 11 has been reviewing suspicious cases, general counsel Julie Goldscheid said. In response to subpoenas, the group has turned over files to the Manhattan district attorney's office.

"It's a delicate balance to guard against fraud and not put up unnecessary barriers," she said.

At the Red Cross -- which has the largest Sept. 11 fund, with more than $947 million in contributions and more than $561 million spent -- a six-member internal fraud review panel has been holding regular conference calls since January to review 30 to 50 suspicious cases, according to spokesman Darren Irby.

Some cases involve questionable survivor death benefits. Others have to do with money given to workers who say they lost jobs.

One woman in the New York area reported her ex-husband dead and collected $20,000. He was not dead. The woman's lawyer contacted the Red Cross and said the money would be returned.

"The Red Cross operates on a foundation of trust that clients are not trying to steal from us," Irby said. The agency requires supporting documentation, but he said: "We've never had a disaster like this before. Usually the fraud that we deal with involves a $250 voucher."

In cases where people do not voluntarily give the money back, the Red Cross has referred "a handful" of cases to law enforcement, spokesman Mitch Hibbs said.

One case under review by the Red Cross involves a Miami man who received tens of thousands of dollars from various charities.

The man, Patric Henn, sought to collect death benefits after he reported that his domestic partner had died in the World Trade Center, according to Matt Foreman, former director of Empire State Pride Agenda, a New York gay rights group, who helped Henn.

Henn told Foreman that his partner had been killed while attending a meeting. Henn said he had no money because they had just bought a home in Florida and the bank had frozen their joint account.

"I didn't find either of those things questionable -- not given the circumstances of those days," Foreman said in a telephone interview.

Henn's case was first reported by the Express Gay News, a Florida-based gay newspaper. The newspaper said Henn told them that he collected more than $25,000 from the Red Cross and Safe Horizon.

Foreman said he lent Henn $1,000 from the gay rights group's general funds, and even cashed the check for him. Later on, Foreman said he made telephone calls to help Henn collect thousands more from the Red Cross and Safe Horizon.

A spokeswoman for Safe Horizon said she could not comment on the case for privacy reasons.

When Henn showed up at the Broward County, Fla., chapter of the Red Cross, the local caseworker knew that his case had been referred from the national office and "reasonably assumed all his documentation had been verified and she didn't collect any more," said spokeswoman Laila Haddad. "She thought he was authentic."

But after no one from the partner's family reported him missing, and discrepancies surfaced during a check of his Social Security number, the charities became suspicious. Henn could not be located for comment.

"This guy was committing fraud against a system that was attempting to be compassionate and treat gay partners equitably," Foreman said. "The system was never set up to handle anything like this."

Staff writer Jacqueline Salmon and staff researcher Bobbye Pratt contributed to this report.