A bus driver involved in a Virginia highway crash early Friday morning that killed at least five people and injured nearly four dozen more has been charged with involuntary manslaughter, Virginia State Police said Saturday. 

Jing S. Dong, 48, of Staten Island, New York, was charged with two counts of involuntary manslaughter, with additional charges pending, police said. Dong suffered injuries from the crash. 

Police said the bus "failed to slow for traffic" and crashed into six vehicles at about 2:35 a.m. Eastern Time on Interstate 95 in Stafford County. The bus first struck a Chevrolet Suburban, which then hit an Acura SUV and additional vehicles. Four people in the Acura were killed, along with one person in the Suburban.  

The four people killed in the Acura, which caught fire after the collision, were identified as a 45-year-old man, a 44-year-old woman, a 13-year-old girl and a 7-year-old boy, state police said. CBS News Boston learned that they were a family of four from Greenfield, Massachusetts, who were on their way to a wedding in South Carolina. They were identified to CBS News Boston as Dmitri Doncev, his wife Ecterina, their daughter Emily and son Mark.

The family wedding will go forward Sunday in South Carolina, but it also will be a time to mourn the family's loss, a relative told the Associated Press on Saturday.

"A son, a father — the whole family — everyone that has been dear to us," Carolina Bublik said.

The family had a carload of homemade desserts for the wedding, which Bublik told the AP that Ecterina had spent days making. 

Dmitri Doncev, 45, was a nurse who worked at Holyoke Medical Center. Ecterina Doncev, 44, was a hairstylist and they emigrated to the U.S. from Moldova in 2008 and settled in Greenfield, Massachusetts, Bublik said.

The victim from the Suburban was identified as 25-year-old Priscilla Mafalda from Worcester, Massachusetts, state police said. 

Forty-four other people were taken to area hospitals, police said, three with critical injuries. There were 34 people aboard the bus at the time of the collision. 

An initial investigation showed traffic was slowing in the southbound lane as cars approached a work zone when the bus failed to slow for traffic, state police said.

The National Transportation Safety Board is also investigating. In a news briefing Saturday, the NTSB said the bus was operated by E&P Travel of Kings Mountain, North Carolina, and was transporting passengers from New York to North Carolina.

"It seems fairly clear that if there was any braking, there wasn't much, because of the speed and the severity of the collision," NTSB member Tom Chapman told reporters, adding that it was still "too early yet to know exactly what was happening on board the vehicle."

The NTSB's preliminary report into the crash will come in the next 30 days. Both state police and the NTSB have said they are looking into the bus driver's actions before the crash.

"One of the things that we do, as a matter of course, is we do a 72-hour look back to see what the driver's activities were during the days leading up to the crash," Chapman said. "So we're looking for, you know, sleep issues, distraction issues, potential drug and alcohol issues."