(CNN) Police in Missouri have launched a homicide investigation after a woman's body was found along the side of a road.

A bicyclist discovered the body on Monday, the McDonald County Sheriff's Office said in a news release. Police believe the woman's body was put into a suitcase and then dumped on a steep hillside.

An initial autopsy performed Tuesday shows no obvious cause of death and no trauma to the woman's body, McDonald County Coroner William Goodwin III said Wednesday.

X-rays showed no broken bones or bullet wounds, said Goodwin.

"As far as the initial autopsy, it didn't show anything at all. We're kind of puzzled," he said. The coroner said DNA and toxicology testing would be done, but fingerprints couldn't be retrieved from the body because the top layer of skin had deteriorated.

Read More