Several relatives of those convicted on Monday wept as the verdict was read out in the Dallas courtroom, with one woman shouting "my father is not a criminal".
Ghassan Elashi, Holy Land's former chairman, and Shukri Abu-Baker, the
charity's ex-chief executive, were convicted of a combined 69 charges, including
supporting a specially-designated "terrorist" organisation, money-laundering and tax fraud, The Associated Press reported.
Mufid Abdulqader and Abdulrahman Odeh were convicted on three counts of
conspiracy, and Mohammed El-Mezain was convicted on one count of conspiracy
to support a "terrorist organisation".
The Holy Land foundation itself was convicted on all 32 counts.
While prosecutors said the foundation raised money for Hamas they did not accuse the charity of directly financing or being involved in "terrorist" activity.
"When you're supposed to be able to face your accusers fully and against secret evidence and secret witness, I think that leads to reasonable doubt"
League of United Latin American Citizens
Prosecutors said the charity was spreading Hamas's ideology by funding schools, hospitals and social welfare programmes controlled by the group in the Palestinian territories, and permitting it to divert funds to the activities of fighters.
However, the charity's supporters said the government was politicising the case as part of its so-called war on terror and ignoring the foundation's charitable mission in providing aid to the poverty-stricken Palestinian territories.
Government officials had raided Holy Land's headquarters in December 2001, and George Bush, the US president, later announced the seizure of the charity's assets as "another step in the war on terrorism".
But defence lawyers said their clients had been put on trial partly because of their family ties to members of Hamas - Khaled Meshaal, Hamas's political leader exiled in Syria, is the brother of defendant Mufid Abdulqader.
Unidentified Israeli witness
Al Jazeera's Tom Ackerman, reporting from Dallas, Texas, where the court case took place, said a former US state department official testified that he was never told that Hamas directed the US charity during intelligence briefings.
But an unidentified Israeli witness told the court that the aid was funnelled through Hamas channels.
Lydia Gonzalez of the League of United Latin American Citizens, said the defendants did not get a fair trial.
"When you're supposed to be able to face your accusers fully and against secret evidence and secret witness, I think that leads to reasonable doubt."
Muslim groups say the prosecution has made American Muslims more hesitant to fulfil their religious obligation of helping the needy and the foundation's defenders accuse the government of selectively prosecuting the charity.
"The same charities that these guys gave to the American Red Cross is still giving to, the USAID is still giving to," Mustafaa Carroll of the Council on American-Islamic Relations, said.