The FBI spent eight years eavesdropping on the Holy Land Foundation, monitoring the Muslim charity's leaders as they met with Palestinian militants and raiding a computer company with strong ties to the group.
But it wasn't until last week that federal officials shut down the group and froze $5 million in assets, claiming the money was being funneled to terrorists.
Why did authorities move so slowly? Political considerations, restrictions on investigations of religious groups and even oversights by immigration officials may have hindered the probe, according to experts on domestic terror investigations.
Holy Land officials accuse the government of mounting a crusade against Muslims. The group, which raised $13 million last year, denies helping the militant Palestinian group Hamas and says it builds schools and provides aid to needy Palestinians and others in the Muslim world.
"This was the Muslims' largest charity, so they are very upset," said Dalall Mohammed, a spokeswoman for Holy Land. She said the raid had left Muslims fearful of donating to any Islamic charity.
After FBI abuses in the 1960s and '70s, the Justice Department adopted limits on investigating religious groups, and the restrictions no doubt slowed the probe into Holy Land, said Fred Moss, a former federal prosecutor and now a law professor at Southern Methodist University.
"Religion stands in a special place in our society, so it's sensitive," Moss said. "If they had found nothing, that could blow up in any administration's face, embarrass the FBI and raise the specter that we're back to the J. Edgar Hoover days."
Mark Briskman, Texas regional director of the Anti-Defamation League, said the Clinton administration feared that shutting down Holy Land would undermine the nation's stature among Arab nations and prevent it from leading Israeli-Palestinian peace talks.
"Clearly, it would have had a negative effect on relations with Yemen, Saudi Arabia and some of the Gulf states," Briskman said.
But political considerations turned against Holy Land after a wave of terror bombings in Israel this month, Briskman said. He said the Bush administration used the raid to show support for Israel.
The FBI took no particular interest in Holy Land until 1993, according to Oliver "Buck" Revell, who headed the Dallas FBI office in the early 1990s when Holy Land moved from Southern California to this Dallas suburb.
That's when three top officials of Holy Land were recorded meeting in Philadelphia with Hamas representatives to discuss helping suicide bombers, according to an FBI memo first reported by the Dallas Morning News and obtained by The Associated Press.
"The target of the investigation was Hamas, and the Holy Land Foundation came up in conjunction with Hamas," Revell said. "There was no indication they were engaged in illegal action at the time."
Revell said the government should have moved to shut down Holy Land as soon as it determined that its money was going to Hamas.
The 49-page FBI report also hinted at FBI frustration with information from immigration authorities about Holy Land leaders.
According to the memo, Holy Land executive director Haitham Maghawri had told the Immigration and Naturalization Service in 1990 that he had been arrested several times in Lebanon, once for placing a car bomb. But the report indicated INS made no detailed notes about the arrests.
Maghawri was denied asylum in the United States, but he gained permanent resident status by marrying a U.S. citizen.
Tim Counts, an INS spokesman in Dallas, said the agency usually investigates arrest reports to determine if an asylum-seeker was persecuted or forced into making a false confession. He said Dallas INS officials did not recall Maghawri's case and would not comment on it anyway.
The FBI report relies heavily on Israeli intelligence and FBI informants to conclude that Holy Land president Shukri Abu Baker and other leaders were members of Hamas and raised money for terrorists.
Holy Land officials denied the FBI charges and called the report a fabrication.
"Ninety-seven percent of what I read in that document was from the government of Israel. I'm shocked that our government is closing our offices based on [reports from] a foreign government," said Mohammed, the Holy Land spokeswoman.
The shutdown of Holy Land came three months after FBI agents raided an Internet company across the street whose officers are involved in the charity.
The freezing of funds is a civil action, and it's unclear whether criminal charges are being considered against Holy Land or its leaders. An FBI spokesman in Washington declined to comment on the investigation, and a Justice Department spokeswoman did not return a call seeking comment.