Twenty-year-old Jennifer Hicks and 24-year-old Gregory Scott, both of Massachusetts, died after being shot at the Buckland Street commuter lot in Manchester on Aug. 2.
Police believe the suspects live in Springfield, Massachusetts or the area and they are looking for a 2016 black Dodge Ram 1500.
Investigators posted two photos on Facebook of the pickup truck from a surveillance camera at a Pride gas station near the MGM Casino in Springfield.
The registered owner of the truck is not the suspect, police said,
Investigators said 100 to 200 people were at the scene at the time of the shooting and could have seen the incident.
The Major Crime Squad is investigating. Anyone with information on the shooting or anyone who may have seen the occupants of the truck in the overnight hours of August 1 into August 2 is urged to call Detective Grabowski at 860-209-1301.