A high rate of speed played a role in a bus failing to slow for traffic approaching a work zone on Interstate 95 in Virginia and crashing into six vehicles early Friday, killing five and injuring dozens, according to NTSB.

NTSB member Tom Chapman said in a news conference Saturday that they’re still in the early phases of the investigation and are not ready to provide any conclusions, but confirmed that the bus was traveling at a high rate of speed.

“We will not be determining the probable cause of the crash while we’re on scene nor will we speculate about the cause,” Chapman said. “These are the first steps in a lengthy investigative process.”

Officials said during the news conference that they will release a preliminary report within 30 days.

According to Virginia State Police, the crash happened around 2:35 a.m. on southbound I-95 in Stafford County, near Quantico.

All five people who died were in vehicles struck by the bus and 44 people were taken to hospitals, including three in critical condition, police said.

The bus failed to slow down while approaching the zone and struck a Chevrolet Suburban, causing a chain-reaction where the SUV crashed into an Acura and other vehicles.

The bus then hit additional vehicles. Police said that coach bus, operated by E&P Travel, was carrying around 34 occupants from New York City to Charlotte, North Carolina.

Four of the people who were killed were inside the Acura: Dmitri Doncev, 45, Ecaterina Doncev, 44, and their children Emily and Mark. They were from Greenfield, Massachusetts.

Priscilla R. Mafalda, a 25-year-old woman from Worcester, Massachusetts, was inside the Suburban that was struck by the bus and died in the collision, according to the NTSB.

State police identified the bus driver as Jing S. Dong, 48, of Staten Island, New York. Authorities said he was charged with two counts of voluntary manslaughter.

The bus was operated by E&P Travel Inc. of Kings Mountain, North Carolina. A compliance snapshot from the Federal Motor Carrier Safety Administration showed one injury crash involving the company’s vehicles in the previous two years and listed its safety rating as satisfactory.

See the briefing below.

WTOP’s Jessica Kronzer contributed to this report.