In a stinging defeat for prosecutors, a former Florida professor accused of helping lead a terrorist group that has carried out suicide bombings against Israel was acquitted on nearly half the charges against him Tuesday, and the jury deadlocked on the rest.

The case against Sami Al-Arian, 47, had been seen as one of the biggest courtroom tests yet of the Patriot Act's expanded search-and-surveillance powers.

After a five-month trial and 13 days of deliberations, the jury acquitted Al-Arian of eight of the 17 counts against him, including a key charge of conspiring to maim and murder people overseas. The jurors deadlocked on the others, including charges he aided terrorists.

Al-Arian, a former University of South Florida computer engineering professor, wept after the verdicts and his attorney, Linda Moreno hugged him. He will remain jailed until prosecutors decide whether retry him on the deadlocked counts.

Co-defendants Sameeh Hammoudeh and Ghassan Zayed Ballut were acquitted of all charges against them. Another, Hatem Naji Fariz, was found not guilty of 24 counts and jurors deadlocked on the remaining eight.

Federal prosecutor Walter E. Furr III, who led the government team, declined to comment afterward.

Al-Arian's wife, Nahla, celebrated outside the courthouse with family members and supporters.

"I'm ecstatic," she said. "My husband is an outspoken Palestinian activist who loved this country, believed in the system and the system did not fail him."

Moreno said the verdicts are a "stinging rebuke" of the prosecution of Al-Arian and she hoped prosecutors would take into account the "overwhelming number of not guilty verdicts" against the defendants in deciding whether to try him again.

"We are so grateful to these jurors," Moreno said. "They worked hard."

She said she will ask the court soon to release Al-Arian from jail.

Al-Arian, 47, is considered one of the most important terrorist figures to be brought to trial in the United States since the Sept. 11, 2001, terrorism attacks. His indictment in 2003 was hailed by then-Attorney General John Ashcroft as one of the first triumphs of the Patriot Act, which was enacted in the weeks after Sept. 11.

The Patriot Act gave the government greatly expanded powers and broke down the wall between foreign intelligence investigations and domestic law enforcement. In the Al-Arian case, officials said, it allowed separate FBI investigations — one of them a yearslong secret foreign intelligence probe of the professor's activities — to be combined and all the evidence used against him.

A male juror, who declined to give his name, said he didn't see the case as a First Amendment issue as defense attorneys had claimed. He said it just came down to lack of proof.

"I didn't see the evidence," he said.

The jury was in its 13th day of deliberations and obviously struggled.

On Monday the panel told U.S. District Judge James S. Moody that they could not reach verdicts on all counts. Moody sent them back to deliberations, and they emerged Tuesday to tell the judge they were hopelessly deadlocked on the remaining counts against Al-Arian and Fariz.

One juror said in a note to the judge that she was being pressured by other jurors to change her vote and could not continue to deliberate.

"My nerves and my conscience are being whipped into submission," the juror said in the note.

Al-Arian, a Palestinian who was born in Kuwait, has lived in the United States since 1975. He was granted permanent-resident status in 1989 and denied U.S. citizenship in 1996. He was fired by USF shortly after he was indicted.

The federal jury heard from 80 government witnesses and listening to often-plodding testimony about faxes and wiretapped phone calls during a trial that lasted more than five months.

The government alleged that the defendants were part of a Tampa terrorist cell that took the lead in determining the structure and goals of the Palestinian Islamic Jihad, which the State Department has listed as a terrorist group.

Prosecutors said Al-Arian and other members of the terrorist organization used the University of South Florida to give them cover as teachers and students, and held meetings under the guise of academic conferences.

Prosecutor Cherie Krigsman likened the Palestinian Islamic Jihad to the Mafia and named Al-Arian as one of its "crime bosses," like TV's Tony Soprano.

The defendants said that although they were vocal advocates in the United States for the Palestinian cause and may have celebrated news of the terrorist group's attacks, the government had no proof that they planned or knew about any violence. They said the money they raised and sent to the Palestinian territories was for legitimate charities.

The case was built on hundreds of pages of transcripts of wiretapped phone calls and faxes, records of money moving through accounts, documents seized from the defendants' homes and offices, and their own words on video. At times, the participants appeared to speak glowingly of the Palestinian "martyrs" who carried out homicide attacks.

"This shows we have faith in the American justice system," said Ahmed Bedier, spokesman for the Council on American-Islamic Relations, which had supported Al-Arian. "This has shown that America is not only the best country in the world, but the jurors proved that we also have the best justice system."

The case figured in Florida's hard-fought battle last year for the Senate, in which former USF president Betty Castor, a Democrat, lost to former U.S. Housing Secretary Mel Martinez. The trial was delayed in part because of the campaign.

Castor put Al-Arian on paid leave in 1996 after learning the FBI was investigating him, but he was allowed to return two years later.

Martinez charged that Castor did not do enough to oust Al-Arian. Castor noted that Martinez's former boss, President Bush, met with Al-Arian during a 2000 campaign stop in Florida.

Five others indicted in the case, including Al-Arian's brother-in-law, have not been arrested. The brother-in-law was deported in 2002, and the others also are out of the country.