WASHINGTON — Between 2006 and 2009, long before he would briefly become infamous, Elton Simpson spent many hours sitting in the Kabob Palace, a Phoenix restaurant, earnestly explaining Islam to a Sudanese friend who said he had converted to the faith.
They talked about basic principles of the religion, according to court records, and also about jihad and what Simpson saw as the obligation to fight to defend the faith in places such as Somalia, where he believed Muslims were under attack.
The friend, Dabla Deng, listened carefully, asked questions and did not let on that he was wearing a wire, recording every word, and being paid by the FBI for his efforts. For 330 conversations lasting hundreds of hours, Deng was paid a total of $132,000 with the sole purpose of catching Simpson in a crime.
The case fizzled. A judge sentenced Simpson to probation in 2011 on a single count of making a false statement. He appears to have complied with probation rules and stayed out of trouble.
Then, on Sunday, Simpson, 30, and his housemate, Nadir Soofi, 34, opened fire at a Prophet Mohammed cartoon contest in Garland, Texas, and were quickly shot to death by a traffic officer. They wounded a security guard in the leg.
A look back at the long investigation of Simpson, which was revived some months ago when he began expressing support for the Islamic State extremist group, shows how elusive a terrorism target can be. The FBI invested a huge amount of labor and money to protect society from Simpson, but he and Soofi still managed to obtain assault rifles and launch an attack.
In retrospect, Simpson’s lawyer in the earlier case, Kristina Sitton, believes that the prosecution did have an effect on him — just not the one the authorities intended.
“He learned that they were following him,” Sitton said Wednesday in a telephone interview. “He learned how not to attract suspicion. He learned how to be a better criminal.”
Sitton said the religious fervor of her former client, who had adopted Islam as a young man, was memorable.
Still, she said, “If you’d have asked me, I would have said he was just a talker.”
In case after case, given the perplexing task of sorting out the talkers from the real terrorists, the FBI has relied on informants to tease out a suspect’s intentions. It is a tactic that many Muslims sharply criticize, saying it divides the community and undermines trust in law enforcement.
Even after Sunday’s shootout, mosque leaders have not changed their opposition to the use of informants.
“If they think there’s someone else at the mosque who is a potential threat, why not work with us?” said Usama Shami, president of the mosque. “We can keep a close eye on him, see who he’s contacting, how he’s acting. We can at least offer some information about that person.”