Law enforcement officials Monday identified the two gunmen suspected of opening fire at a Garland, Texas, event featuring cartoon drawings of the Muslim Prophet Muhammad. Both men lived in Phoenix, and one of them had been known to the FBI for years and previously convicted of lying to federal agents, the New York Times reported.

Elton Simpson, 30, a convert to Islam, came to the FBI’s attention as early as 2006, the Associated Press reported. The FBI then worked with an informant to record more than 1,500 hours of Simpson’s conversations, including in 2009 discussions of his plans to travel to Somalia.  

“It’s time to go to Somalia, brother,” Simpson said in one of the recordings, according to court filings cited by the Wall Street Journal. “We gonna make it to the battlefield.”

Prosecutors accused Simpson of making plans to join up with Islamic militants abroad and of lying to federal agents about it. Ultimately, a federal judge ruled prosecutors didn’t establish Simpson’s plans were “sufficiently ‘related’ to international terrorism,” the Journal reported. Simpson was given three years’ probation in the case.

The second man, Nadir Hamid Soofi, 34, had not been investigated by the FBI, the Times reported. He was born in the U.S., a relative told the Times, while a Facebook page appearing to belong to Soofi said he attended the International School of Islamabad in Pakistan and the University of Utah.

Simpson and Noofi used to attend the same mosque, Usama Shami, president of the Islamic Community Center of Phoenix, told the Times. Simpson was popular among the boys at the mosque, and his questions about Islam “were pretty basic and religious,” Shami said.   

FBI officials and police Monday canvassed the Phoenix apartment complex where Simpson and Soofi were roommates, Reuters reported.

Both suspects were carrying assault rifles Sunday when they were shot and killed by a police officer outside of the art show organized by the American Freedom Defense Initiative. A school district security officer was shot in the ankle.