MIDDLETOWN TWP., Pennsylvania (WPVI) -- Officials have identified the arm found in Fox Chase earlier in the week as belonging to Alexandra Ridgway, the victim of a hit-and-run crash on Route 1 in Bucks County.The arm was recovered in the 8800 block of Pine Road hours after the early morning crash on Monday.Police said Ridgway was struck by multiple cars and ultimately killed while either walking on or attempting to cross Route 1 near the Neshaminy High School exit.The roadway was shut down in both directions for several hours Monday morning as police investigated."We had traffic from 5:30 on, we heard a lot of backing up, beeping trucks, things like that," said homeowner Stacy Allen. "I thought it was an accident because it's usually very good, the (traffic) flow is good, I love living here so I knew it had to be something crazy."Middletown Township police released a statement saying Ridgway was struck by multiple cars on the southbound side of the highway; none of the striking vehicles remained at the scene.Later Monday afternoon, Philadelphia police said human remains were discovered around 8:30 a.m. that morning along the 8800 block of Pine Road in Fox Chase. Police said during the collection of evidence from the crash scene a chrome-plated piece of plastic from the front grill of a Mack Truck was recovered.With assistance from Mack Truck dealers and Mack Truck part suppliers in the area police determined this grill assembly piece was manufactured for Mack Trucks, Pinnacle series, model year 2004 through 2007.Police said this series of Mack Truck will be a tractor-trailer combination, and the evidence strongly suggests that this type of truck may have been the initial striking vehicle that then fled the scene.Investigators also said the damaged area to the front of this truck would be noticeable and substantial and even potentially disabling.Alerts have been issued to all certified Mack Truck repair facilities in the area to be on the lookout for a Mack Truck that may need these types of repairs.Middletown Township Police continue to investigate the crash and ask anyone with information to contact them.