Drivers drove into and killed two pedestrians over the weekend in two separate incidents in Chelsea and East Wareham.

On Friday night, around 9 p.m., state police responded to a crash on Route 25 in East Wareham, where they found the evening’s first victim, identified as Lisa Sullivan of Sandwich, suffering from serious injuries. Sullivan was later pronounced dead at a nearby hospital.

The driver who killed Sullivan, identified only as a 36 year-old woman from Pocasset, reportedly stayed on the scene and is not yet facing any charges. State police say that the killing remains under investigation.

Route 25 in Wareham is a six-lane freeway with no sidewalks that links Interstate 495 with the Bourne Bridge to Cape Cod. Police are still trying to determine why Sullivan was walking on the roadway.

Later that same night, near midnight, another driver, Ian Flynn of Peabody, drove his car into a pedestrian at Sixth and Walnut Streets near the Chelsea commuter rail stop. Flynn subsequently fled the scene, but witnesses were able to record his license plate number, and police later arrested Flynn and seized a vehicle that allegedly matched witnesses’ descriptions at Flynn’s Peabody residence.

Flynn’s victim, later identified as 31 year-old Jeffrey Jean-Charles of Everett, was transported to CHA Everett Hospital and later pronounced dead.

Chelsea and State Police have charged Flynn with driving while intoxicated (allegedly his second offense), leaving the scene of an crash that caused personal injury and death, and negligent operation of a motor vehicle. The killing remains under investigation and additional charges may be filed.