A federal grand jury has apparently been convened to investigate the Fundamentalist LDS Church in the aftermath of the raid on the Utah-based polygamous church's Texas ranch.

Lawyers for FLDS leader Warren Jeffs are accusing Texas and Arizona authorities of blocking their efforts to ferret out the origins of the raid on the YFZ Ranch.

In a court filing made public in Kingman, Ariz., on Thursday, Jeffs' criminal defense attorneys complain that Texas law enforcement officials forbade any inquiry into the apparent hoax call that sparked the raid, where hundreds of children were taken into state protective custody.

Excerpts of interview transcripts filed with their complaint also revealed the apparent federal grand jury probe.

"This is all part of what has become a pattern of obstruction on the part of Texas law enforcement authorities," attorneys Richard Wright and Michael Piccarreta wrote. "The state of Texas simply would not allow any questions showing that the Texas law enforcement authorities now know that their search warrant affidavits were full of lies."

Jeffs' attorneys are seeking to prevent evidence taken from last year's raid from being used in his upcoming trial in Arizona, where the 53-year-old is accused of performing underage marriages. He was convicted in Utah of rape as an accomplice for performing an underage marriage.

Jeffs' defense team questioned Schleicher County (Texas) Sheriff David Doran, one of his deputies and Texas Ranger Brooks Long. But when the attorneys started asking about Rozita Swinton, the woman suspected of making the phony phone calls, interview transcripts showed that Texas authorities objected.

"I can't comment on that simply because I would be violating federal law in reference to that particular question," Long said in the interview.

"And what, why is that, because," Piccarreta wondered.

"Because I'm on the 6(e) list," Long replied, referring to federal rules of criminal procedure on grand jury secrecy.

"A grand jury list," Piccarreta said.

"Yes."

"And all right, so in terms of those calls and whether or not they relate to Rozita Swinton, that's something that you don't feel that you can disclose."

"It's not me personally, it's just, I would be violating federal law if I commented on that at this time."

Assistant Texas Attorney General Eric Nichols also halted many of the questions, citing an ongoing investigation by the state.