Police investigating the shooting death of a Maine motorist in the dead of night on a Pennsylvania interstate last weekend said Friday they did not think it was related to another roadway shooting about seven hours earlier some 50 miles away.

Members of a team trying to solve the Jan. 4 killing of 28-year-old Timothy Davison along Interstate 81 also said they did not think it was linked to the unsolved shooting of a Kentucky state trooper along a highway in May.

Pennsylvania State Police Capt. Steven Junkin said at a news conference a few miles from the shooting scene that the assailant is believed to have been a man driving a dark-colored Ford Ranger XLT pickup truck that likely has damage to its front driver's side. That model of pickup has not been made for about a decade, he said.

Because the shooting occurred around 2 a.m., the color of the pickup is not certain, but police said it may be blue. Investigators have asked body shops in Pennsylvania, Maryland and West Virginia to look out for such a vehicle.

Davison died of multiple gunshot wounds, although authorities are not disclosing the type of weapon used.

Junkin says the suspect apparently pursued Davison on Interstate 81 northward for about 15 miles, from Interstate 70 in Maryland to a few miles into Pennsylvania. He said the driver is believed to have then turned around and headed south.

There is no evidence that Davison, who made several calls to 911 while being pursued, did anything to provoke the attack.

"This actor had murderous intent," Junkin said, surrounded by other members of a task force set up to investigate the crime. "We obviously have an individual who was so incensed that he continued to pursue Mr. Davison."

Trooper Adam Reed said authorities are still trying to piece together how the shooting occurred, and are not sure whether it can be described as a case of road rage but cannot rule it out.

Davison, an outdoorsman who worked as a pipe fitter and welder, was traveling home after visiting family members in Florida when the shooting occurred. Family and friends in and around his home in Poland, Maine, are preparing for his funeral on Saturday.