"At best we're about three to six months before finishing it," said Gill, "and then we'll be in a position to see if that results in any criminal filings or not."
Lawson, described as Shurtleff's "fixer," is charged with six felonies, while the lieutenant governor's office deemed that Swallow committed five election-law violations in his campaign for attorney general. It declined to press charges once Swallow resigned in early December.
Investigators for a Utah House special committee, which is preparing to release its final report, determined that Swallow fabricated documents and destroyed evidence to cover up politically damaging ties to questionable campaign donors and favors done for those contributors.
Evidence in those two probes has been turned over to the county attorneys.
Working with Gill and Rawlings on the investigation are four other attorneys from their offices, a state investigator and seven FBI agents. Another 10 to 15 FBI agents who are attorneys, including from other states, also are assisting.
The U.S. Justice Department had been conducting its own investigation. But the agency notified Swallow and Shurtleff, both Republicans, in September that it would not file charges.
Gill expressed frustration with that decision Tuesday, saying some of the issues his and Rawlings' investigation have uncovered are ones "we might not be able to touch" and that "would be more appropriate at the level of the Department of Justice."
"Certainly, there are other entities that could have done this," Gill said, "and that may fit more pragmatically in their portfolio in terms of their resources and some of the flexibilities they may have."
Last week, the Utah Democratic Lawyers Council called on the feds to reopen their investigation.
Gill said the FBI's continued involvement with the county prosecutors "is certainly unique about this case, and I think it speaks well to their commitment and the seriousness with which they are taking these issues."
The team has gathered more than 20,000 pages of documents.
Swallow's lawyer was not immediately available for comment. Shurtleff's attorney did not respond to an email request seeking comment.