Police work at the scene of a fatal crash Tuesday. PHILIP HOLMES/Sun-Gazette

An investigation is underway into the cause of death of a Williamsport motorist whose SUV crashed into the back of a stopped westbound River Valley Transit Authority bus on West Fourth Street in the city’s Newberry neighborhood about 5:50 p.m. Tuesday, Lycoming County Coroner Charles E. Kiessling Jr. confirmed.

“It sounded like a big explosion. It hit so hard,” an elderly woman who heard the crash in front of her home, just east of Poplar Street, said.

As soon as emergency crews arrived on the scene, they began performing cardiopulmonary resuscitation on the SUV driver, who was rushed by ambulance to UPMC Williamsport, city police said. Efforts to save him were unsuccessful. Kiessling said the driver, who was in his mid-60s, was the sole occupant in the SUV.

The bus driver and the two passengers on the bus were not hurt, police said.

Kiessling said investigators will be reviewing the decedent’s medical records before making any final determination on the man’s cause of death.

A towing company works to remove the wreckage from Tuesday night's crash on West Fourth Street in Newberry. PHILIP HOLMES/Sun-Gazette

City firefighters also responded to the accident, which remained under investigation. The man’s identity was expected to be released after family members were notified.

City firefighters were among the emergency responders who were dispatched to the crash. PHILIP HOLMES/Sun-Gazette