DALLAS – The Holy Land Foundation for Relief and Development was once the largest Muslim charity in America, but federal prosecutors argued today that underneath its surface lay an ominous goal: financing international terrorism.

After two months of testimony, closing arguments began today in the trial of the foundation and five of its leaders on charges of aiding terrorists, conspiracy and money laundering.

The defense says the foundation was helping ordinary Palestinian Arabs in need.

Prosector Barry Jonas told the jury today that the Holy Land Foundation wasn’t a normal charity at all. Authorities allege the foundation funneled more than $12 million to Palestinian schools and charities controlled by the militant group Hamas after the U.S. government declared Hamas a terrorist group in 1995, which made supporting it illegal.

If the men are found guilty and the jury determines their actions resulted in deaths, the men could face up to life in prison.

The case may hinge on whether the jury believes Hamas controlled the Palestinian Arab charities that received money.

One retired American diplomat, Edward Abington, testified that the charities that received Holy Land Foundation money were not under Hamas control.

Former Texas congressman John Bryant, who briefly represented the foundation, also testified, saying he asked the FBI and State Department to warn him if any of the charities had terrorist ties but got no response.

The government’s case relies heavily on thousands of pages of documents such as bank records and on video and audio tapes that showed some of the defendants meeting with Hamas members and supporters.

A letter sent to Shukri Abu Baker, Holy Land’s chief executive, assessed whether leaders of the Palestinian Arab charities were friend or foe.

At one charity, the unknown author told Baker, “We have nobody in it,” but at another, “All of it is ours and it is guaranteed.” An FBI agent said the latter reference meant that Hamas controlled the group.

But the letter, and much of the other evidence in the case, dated to the early 1990s or before. And a key witness who claimed the Palestinian Arab charities were Hamas fronts was an Israeli official who was allowed to testify without being identified. He acknowledged that none of the groups appeared on American government terrorist lists.

Prosecutors declined to call many of the people on their witness list, including Mohamed Shorbagi, a former Holy Land representative who pleaded guilty last year to supporting Hamas. He was supposed to testify about the relationship between Dallas-based Holy Land Foundation and Hamas, according to a court filing by prosecutors.

A former federal prosecutor in Dallas, Tom Melsheimer, said such insiders are invaluable in document-heavy cases.

“Normally in those cases, you have a witness or participant who can give some sense of what was going on when the documents were created,” he said.

In addition to Mr. Baker, the men charged are former Holy Land Foundation chairmen Ghassan Elashi and Mohammed El-Mezain, former fundraiser Mufid Abdulqader, and Abdulrahman Odeh, described as the group’s representative in New Jersey. Two other men named in the indictment were never arrested and are believed to be in the Middle East.

The Holy Land Foundation was shut down in December 2001 and its assets were seized by the federal government.