Tampa, Fla. ? 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 return to jail until prosecutors decide whether to retry him on the deadlocked charges.