Amos Mortier confronted a drug associate four days before he disappeared, according to testimony Thursday at a federal court hearing in Madison. Mortier was short on money and was convinced the drug associate had robbed him of thousands of dollars of marijuana.

Phone records show the associate, Jacob Stadfeld, then called several gun shops around Dane County, Fitchburg police Detective Shannan Sheil Morgan testified.

Then on Nov. 8, 2004, the day Mortier was last seen, Morgan said, cell phone records show Stadfeld was at or near Mortier’s house around the same time that Mortier’s cell phone, which is still missing, was turned off for the last time.

Those details surrounding Mortier’s disappearance, discussed in open court for the first time, came Thursday during a three-day hearing before U.S. District Judge Stephen Crocker, who will decide this summer whether Stadfeld and another Mortier associate, Brent Delzer, were given immunity from federal drug prosecutions during interviews with state-level authorities in 2004 and 2005.

Stadfeld, 32, and Delzer, 35, were indicted last year for allegedly taking part in a large-scale marijuana distribution conspiracy linked to Mortier that has landed several other people to federal prison.

Police and prosecutors said during the hearing that Stadfeld is a prime suspect in Mortier’s disappearance and presumed death. He has not been charged with any crime related to it. Dane County Assistant District Attorney Corey Stephen said he could not comment on any potential charges.

Investigators, trying to learn early on what both men knew about Mortier’s disappearance, said they would not prosecute Stadfeld or Delzer for drug crimes if they gave truthful statements. Assistant U.S. Attorney Dan Graber asserted immunity from federal prosecution was not part of the deal, and both men breached the agreements by lying or being less than candid during meetings with investigators.

Morgan testified that during one of those meetings, Stadfeld lied about his whereabouts on Nov. 8, 2004. Stadfeld claimed he drove by Mortier’s home about 5 p.m. and saw nothing out of the ordinary.

But Morgan testified cell phone records show that at 3:30 p.m. on Nov. 8, 2004, Stadfeld’s phone “hit” the cell tower on Blaney Road in Fitchburg, on a part of the tower that a phone would use at or near Mortier’s home on Lacy Road. Records also showed that sometime between 3:30 and 4 p.m., Mortier’s phone was turned off for the last time, Morgan said.

Stadfeld also claimed that on Nov. 9, 2004, he left his home at 10 a.m. and drove to Mauston to visit his mother, arriving around 11:30 a.m, Morgan said.

But she said cell phone records revealed he was at or near Mortier’s house at 10:05 a.m., in Portage at 12:30 p.m. and Wisconsin Dells about 7:30 p.m. before returning home.

Reed Rogala, who was Mortier’s marijuana source and is serving a 12-year prison sentence, testified that about a week before Mortier vanished, Mortier realized Stadfeld may have stolen a large amount of marijuana from him and owed him about $80,000.

In September 2003 Mortier feared being robbed. Stadfeld offered to store a hockey bag full of marijuana, a shipment from Rogala, at the condo of Stadfeld’s friend, Fred Schubert. But on Nov. 30, 2003, while Schubert was out of town, his condo was burglarized. The only thing taken was the hockey bag.

Schubert testified that Stadfeld, who had a key to the condo, was the only person who knew the marijuana was there. Town of Madison police officer Todd Dart said the burglar did not take electronic goods that would have been easy to pawn.

Rogala’s former girlfriend, Destin Layne, testified that on Nov. 4, 2004, after Mortier realized he was deep in debt to Rogala, she picked up a copy of Dart’s report for Mortier. Mortier suspected the burglary was faked, she said. Morgan said phone records showed Mortier called Stadfeld. Stadfeld then started calling gun shops, Morgan testified.