Ottawa ? An investigation into the death of an Ottawa University student has been reopened after the man’s parents complained that authorities overlooked evidence that their son was killed and did not accidentally drown.

Kevin and Debbie Heidt, of Morrison, Colo., said their son, Derrick, called them panicked the night before his body was found last spring at Pomona Lake. He told them his car was being followed and he had gotten lost while trying to get away.

Kevin Heidt used a map to help his son find his way from the Pomona Lake area back to Ottawa.

“I lost the connection,” the elder Heidt said. “That was the last time I talked to him.”

Sixteen hours later, authorities went to the couple’s Morrison home and told them their son was dead.

His parents have remained skeptical of Osage County authorities’ ruling that the death was an accidental drowning.

They said their son was an expert swimmer and that their funeral director told them marks on his body were inflicted by some sort of trauma. The couple hired a forensic pathologist, and Kevin Heidt said the pathologist found evidence that mud and dirt had been forced into their son’s throat.

“I am aware of how my son looks, and all the pictures, and they don’t jibe with the story I was given,” Kevin Heidt said Monday.

Before his death, the couple said their son had sought to distance himself from friends who sold marijuana and other drugs. Kevin Heidt said three acquaintances were arrested on drug offenses three days before their son’s death.

“He was worried that they thought he turned them in,” Kevin Heidt said.

Their questions prompted Sheriff Lori Dunn to request the Kansas Bureau of Investigation review.

Ray Lundin, a KBI special agent, said the agency is trying to find people who might be involved or could provide information.

“There are a couple of folks we haven’t been able to contact,” Lundin said.

The Heidts hope the reopened investigation will provide more answers.

“We hope someone knows something or remembers something and calls the KBI,” Heidt said.