POLAND, Maine — Pennsylvania police still have no solid leads in the suspected road rage killing of a Maine resident more than 18 months ago, but a Maine-based reward for information about the case has grown to $52,000.

Pennsylvania Crime Stoppers is offering an additional $10,000 reward for information leading to the identification and capture of the suspect.

Timothy “Asti” Davison, 28, was shot and killed in the early morning hours of Jan. 4, 2014, while driving alone on Interstate 81 in Franklin County, Pennsylvania, according to Pennsylvania State Police.

On Thursday, Davison’s mother, Theresa Allocca, said friends and family raised the reward money in hopes anyone with information would come forward.

“Some people through our website brought it up, and we as a family talked about it and said, ‘maybe it is a matter of money,’” Allocca said. “So we raised it.”

She said more than 66,000 people have seen her most recent Facebook post offering the reward money. Between the social media site and the Justice For Asti website, she said they have collected more than 200 tips.

“A lot of those tips are of license plates on trucks or of strange people with a truck that matches the one used,” Allocca said. “We don’t filter those tips at all. I am constantly forwarding them to the Pennsylvania police.”

Police there say Davison was driving northbound on I-81 when he was chased by an unknown assailant who rammed Davison’s sport utility vehicle into the median strip.

The man then got out of what is described as a dark blue Ford Ranger pickup truck and fired several shots into Davison’s vehicle, killing the Poland native before getting back in his truck and fleeing in the southbound direction.

“There is nothing new in this case, but we continue to investigate,” Officer Rob Hicks, spokesman for Pennsylvania State Police Troop H in Harrisburg, said Thursday. “We still continue to get tips, though they have slowed down, and we continue to follow them up to see where they lead us.”

Hicks said his department is aware of the reward being offered from Maine, and investigators are still in contact with Davison’s family in the state.

Allocca said she talks to Hicks weekly for any updates on the case and is confident it ultimately will be solved.

“It’s just a matter of time,” she said. “No sane person goes around shooting people, and I think it’s a matter of time before someone hears that person running their mouth off and thinks, ‘I would like $62,000.’”

Hicks said police are not giving up.

“I know our guys are working hard to get this case solved,” Hicks said. “They want to get it solved, especially for the family so they can have some closure.”

Davison reportedly was driving home to Maine after visiting relatives in Florida for the Christmas holidays when he called 911 to report he was being pursued by the driver of what appeared to be a Ford pickup truck. Police say the pickup truck likely sustained driver’s side or front-end damage.

According to the Justice for Asti Facebook page, family and friends of Davison are hanging posters and flyers along the I-81 corridor from West Virginia to Pennsylvania requesting information about the shooting.

Allocca said she receives calls from people who follow the case on social media requesting flyers to put in areas along I-81.

In the meantime, Allocca said she and her three remaining children struggle with the loss of “Asti” daily, as she recalled the young man who loved to grill food outdoors, both summer and winter, in Maine and was loved by so many people.

“As a parent, it is really difficult,” she said. “You have all these new holidays, and you are constantly trying to figure out what the new ‘normal’ is. It’s been hard on his sisters, brother and his grandparents and cousins.”

Finding her son’s killer remains Allocca’s No. 1 priority.

“I focus a lot on trying to get this solved,” she said. “It keeps me busy.”

Hicks said anyone with any information is urged to call the Pennsylvania Crime Stoppers at 1-800-4PA-TIPS.

Information may also be left online at Justice for Asti at justiceforasti.com.