Attorney Art Folsom told The Denver Post while Najibullah Zazi was released Wednesday by authorities at the Byron G. Rogers Federal Building in Denver, his client was scheduled to take part in additional questioning Thursday.
Zazi's apartment was raided Tuesday by federal agents as part of a multistate terror investigation. A second property where Zazi's aunt and uncle live was also raided.
Denver FBI spokeswoman Kathleen Wright did not offer specifics regarding the ongoing investigation, which focused on the use of peroxide-based explosives as part of a suspected terror plot, the Post said.
Folsom said Wednesday night the raids likely proved fruitless given his client's release following FBI questioning.
"If they found so much as a gram of explosives there, then Mr. Zazi would not be leaving the FBI offices with me tonight," Folsom told the Post.