FARGO - A preliminary autopsy report concluded that a body found Saturday was indeed that of Dru Sjodin, and that the University of North Dakota student was a victim of homicide, Polk County officials said Tuesday.

A final report will be completed by the Ramsey County Medical Examiner's Office in St. Paul, Minn., said Greg Widseth, Polk County attorney. A statement from Widseth gave no detail on how she died.

"It's the final piece to the puzzle for what they are working on," said Sgt. Michael Hedlund, Grand Forks police spokesman. "There are still things to be reviewing and preparing, and where the case goes from here remains to be seen."

Asked if he was surprised by the preliminary results, Hedlund said, "No, unfortunately."

Widseth said he would not release further details. Polk County Sheriff Mark LeTexier had no comment.

The body of Sjodin, 22, was found near a county road northwest of Crookston, about five months after she was last seen at a Grand Forks shopping mall.

Alfonso Rodriguez Jr., 51, a convicted sex offender from Crookston, is charged in Grand Forks County with kidnapping her. He has pleaded not guilty.

Final autopsy results are expected to be completed in the next few weeks, Widseth said. State and federal authorities continue to investigate the case.

Drew Wrigley, the U.S. attorney for North Dakota, said prosecutors have agreed on whether the case will be tried in federal or state court. But he declined to say what that decision was.

He said the decision was based on "facts and several practicalities," but declined to elaborate.

"Right now it's more important to talk about keeping our thoughts and prayers with Dru and her family," Wrigley said.

Wrigley met with Grand Forks County prosecutors and law enforcement officials in Grand Forks on Monday. Thomas Heffelfinger, U.S. attorney from Minnesota, had trouble making travel arrangements and couldn't attend the meeting, Wrigley said.

"You shouldn't read anything into that," Wrigley said.

Heffelfinger said only that he and Wrigley continue to discuss the case.

"You would assume and you would be disappointed if we weren't talking," he said. "On any matter, that's how we do business. There's no doubt this matter is of equal importance to both states."

Joseph Daly, a criminal law professor at Hamline University in St. Paul, said he believes the trial will be held in federal court in North Dakota.

"The crime originated in North Dakota, and she was going to the University of North Dakota," Daly said. "This has deeply affected people in both states, but North Dakota has probably been more traumatized."

At an earlier court hearing, investigators said that traces of DNA matching samples from Rodriguez and samples from Sjodin's toothbrush were in spots of blood found in Rodriguez's car. Investigators say they also found a knife in the trunk of Rodriguez's car that matched a sheath found near Sjodin's car.

Rodriguez had been released from prison in May after serving a 23-year sentence for an attempted kidnapping and assault of a woman in 1980.

Sjodin's family planned a private visitation for Friday in Crosslake, Minn. Her funeral will be Saturday afternoon in Pequot Lakes. Burial is planned for Pinewood Cemetery in Crosslake.

(Well-wishers can send messages to the family on the Brenny Funeral Chapel Web site at http://www.brenny.com/obits.cfm.)