Lambton OPP say a 43-year-old cold case may not have been a murder, but instead, a motor vehicle collision.

Karen Caughlin was last seen alive on March 15, 1974.

She went to a Point Edward roller rink with friends and was dropped off at a Brock Street home just before 1 a.m.

Caughlin's remains were found the next morning in a ditch 22 kilometers awaynear the side of the then-6th Sideroad or Freer Road, now known as Plowing Match Road, between Churchill Line and Lasalle Line.

At a news conference on Thursday, police said Caughlin's injuries are consistent with a motor vehicle collision.

Police say her body was moved from where she sustained the fatal injuries to where she eventually discovered.

Investigators say they have received more information from the public and have conducted subsequent analysis over the last three years to support this theory.

Police say a lack of visibility that night because of fog, along with her clothing, motorists may not have seen her walking close to the roadway.

OPP have been investigating this case for decades, even offering a $50,000 reward for information. But that has not lead to any arrests in the case.

"The OPP understands and sympathizes with families who have lived with the tragic loss of a loved one. Karen Caughlin's family has endured this tragedy for 43 years and have missed experiencing annual gatherings, celebrations and life events that form the lives we aspire to live. We know people know what happened to Karen and strongly urge them to come forward. The family deserves the resolution we have been seeking," said Detective-Inspector Chris Avery, Commander, OPP Lambton County Detachment in a news release.