More than four months after Thomas Bearson's death, the search for his killer goes on.

Fargo and Moorhead police held a joint news conference Monday to offer their worried communities an update on the homicide investigation, and to ask for help locating a vehicle seen in the area where the 18-year-old's body was later found.

"This is still a very active case," Moorhead Police Chief David Ebinger told reporters. "As a result, we have to be circumspect."

Details were scarce, but investigators did try to debunk a few of the rumors swirling around Bearson's death. No, his body wasn't mutilated. No, he didn't die of a drug overdose or from alcohol poisoning. No, he wasn't believed to be working as a confidential informant for police at the time of his death.

Investigators still couldn't talk about how Bearson died, or why. No suspects in his homicide have been identified. But police are searching for a four-door passenger vehicle captured on video surveillance in the vicinity of the Moorhead RV dealership where Bearson's body was found, three days after he vanished.

The case remains "on the front burner," Ebinger said. "I feel hopeful. … There's good work being done here."

The death of the smiling, charismatic student from Sartell has shaken the campus communities around Fargo and shattered his family and grieving hometown back in Minnesota.

Bearson was last seen at 3:40 a.m. on Saturday, Sept. 20, leaving a house party in Fargo. It was the first month of his freshman year at North Dakota State University and his dorm room was just six blocks away.

Searchers found his body three days later, 5 miles away on the other side of the Red River, in the lot of Larry's RV Sales in Moorhead. Bearson's left tennis shoe, a white Nike Air Jordan, size 9 ½, and his silver iPhone 5 were missing from the crime scene. Neither have been found.

Police from Moorhead, Fargo and NDSU launched a joint investigation into his death, along with the Minnesota Bureau of Criminal Apprehension and the FBI. Monday's community briefing came after Moorhead police received the final results of the Ramsey County Medical Examiner's autopsy report on the case.

Bearson was the second college student found dead on the banks of the Red River last year. The first victim was 20-year-old North Dakota State College of Science student Andrew Sadek, who had been working as a police informant before his death.

"This is still one of the safest places to live or send your kid to school in the country," Ebinger said. "We intend to keep it that way."