By Mary Snow
(CNN) - A double murder mystery remains unsolved in Mississippi.
At least two people were killed while driving down lonely state roads at night.
Tom Schlender, 74, was the first victim found dead in his car, shot multiple times, on a remote stretch of highway in Mississippi.
He was driving from Nebraska to Pensacola, Florida to pick up his grandson at college. His family says his wallet was missing when he was found and that there was no indication of any problem when he spoke to his daughter by phone, just hours before his death.
"It's hard to imagine your father in that situation," said his daughter, Tracy Anderson.
"This is a violent end to a very kind man's life," said Schlender's son-in-law, Matthew Anderson.
Schlender was found May 8th at 1:30 a.m.
Three days later authorities found a second victim dead outside her car at 2:15 a.m., 55 miles from the first murder scene. She is identified as 48-year-old Lori Anne Carswell and authorities say she was on her way home from her job at a casino.
"A common denominator we have between both incidents is that we believe both vehicles were on the side of the road," said John Champion, the DeSoto County District Attorney.
That's why authorities believe the killer may be posing as a police officer. They say nothing was wrong with the victims' cars.
Forensic teams are comparing shell casings from both locations.
Mississippi drivers have been told to be on alert. If they are suspicious of a police car pulling them over, they're advised to put on their hazard lights and dial 911 to verify it's legitimate or wait to pull over in a well-lit, crowded place.
But as one law enforcement analyst points out, the possibility of someone posing as a fake officer is just one theory.
"There is no vehicle description, there is no description of anyone involved in this. So could it be someone who maybe was pulled over to the side of the road and these victims were Good Samaritans, and pulled over to help this person? That's also another scenario that has to be looked at by law enforcement," said Mike Brooks.
US Marshals and the ATF are working with law enforcement in Mississippi. In addition to providing forensic experts, the ATF says it is also working with FBI profilers to find the killer.