Two friends of a missing Fitchburg man were indicted Thursday by a federal grand jury on charges of conspiring to distribute large amounts of marijuana, bringing to six the number of people charged in relation to the case.

The indictments for Jacob Stadfeld, 32, and Brent Delzer, 34, were filed Friday in U.S. District Court. The indictments allege that the two conspired between themselves and others to distribute marijuana from about 2000 until Nov. 8, 2004.

That's the date that Amos Mortier was last seen before he vanished from his home in Fitchburg, leaving his dog running outside and a record spinning on his turntable.

It is unclear how the marijuana conspiracy is related to Mortier's disappearance. However, a plea agreement for Reed Rogala, 32, of South Orange, N.J., who pleaded guilty in June to involvement in a marijuana distribution conspiracy, gives Rogala immunity for any further statements he makes, except those pertaining to his "involvement, if any, in the murder of Amos Mortier."

In search warrants filed in 2005, Delzer told Fitchburg police that over the previous two years, he had sold "pounds" of marijuana for Mortier. He also said that Mortier was owed $90,000 by Stadfeld for marijuana that Mortier had given him to sell.

Delzer also told police, according to the warrants, that four or five days before Mortier was last seen, he was at Mortier's home when Mortier received a phone call and began to yell that someone owed him money. That surprised Delzer, the search warrants state, because he had never heard Mortier yell.

Phone records showed that the call may have been from Stadfeld, warrants state.

Police also interviewed Stadfeld about cell phone calls he made to Mortier on the day he vanished and the days prior.

Other friends of Mortier have also been charged with involvement in a marijuana distribution conspiracy. Destin Layne, 30, who described herself as a mentor to Mortier, was charged on Aug. 12 and is set for a plea hearing on Sept. 17.

Rogala, a former UW-Madison student, will be sentenced on Nov. 6. Rogala's former roommate, Brian Hutchinson, also a former UW-Madison student, entered a guilty plea on Aug. 11 and will be sentenced on Oct. 29.

Federal prosecutors on Aug. 14 also charged Hal Taback with involvement in the conspiracy.

According to information presented by prosecutors in court during Hutchinson's plea hearing, Taback was among Rogala's sources for marijuana in New York, which Rogala had brought to Madison in hundred-pound loads by hired couriers.