Investigators in the US pleaded on Saturday for members of the public to come forward with information that could help them determine why a pickup truck hauling a trailer collided with a group of 10 motorcycles on a rural highway, killing seven bikers.
The crash in remote northern New Hampshire involved members of Marine JarHeads MC, a motorcycle club that includes Marines and their spouses, authorities said.
The tragedy sent shock waves through New England's communities of motorcyclists and military veterans, which often overlap.
"When something like this happens, we all feel it," said Cat Wilson, who organises a motorcycle charity event in Massachusetts and is a friend of some of the crash victims.
"There is no tighter community than our biker community."
Authorities identified the pickup driver as Volodoymyr Zhukovskyy, 23, an employee of a Springfield, Massachusetts, company called Westfield Transport.
Zhukovskyy survived the accident, did not need to be hospitalised and has not been charged, authorities said, but they didn't address details on his whereabouts. A phone listing for him couldn't be found.
Dartanyan Gasanov, the owner of Westfield Transport, told The Boston Globe that he planned to talk to investigators Monday and has been unable to reach Zhukovskyy, who has not been answering phone calls.
The National Transportation Safety Board is among the agencies investigating.
Authorities asked for the public's help in the form of videos, photos or other information about the accident or the vehicles involved.
"This is one of the worst tragic incidents that we have investigated here in the state," New Hampshire State Police Col Chris Wagner said at a news conference in nearby Lancaster. "It's going to be a very lengthy investigation."
A 2016 Dodge 2500 pickup truck towing a flatbed trailer of the kind used to haul cars collided with the bikers around 6.30pm on Friday on US 2, a two-lane highway in Randolph, police said.
Randolph is about a two-hour drive north of Concord, the capital, and a three-hour drive from Boston.
Along with the seven dead, state police said, three people were taken to hospitals. Two of them were released Saturday.
Police did not provide names of the injured or dead but said they could release the names of victims as early as Sunday.
The road reopened on Saturday, and skid marks were still visible on the road, which has mountains and fields as a backdrop. A patch of burned grass remained.
Bill Brown, a 73-year-old military veteran and motorcyclist, arrived at the scene near a gentle curve in the road to plant flags, calling the victims "brothers in arms" and vowing to keep riding.
Members of the motorcycle community are already organising help for the victims' families, Wilson said.
A small memorial was held at a church in nearby Berlin on Saturday evening.
The pickup truck was on fire when emergency crews arrived. Witnesses described a "devastating" scene as bystanders tried to help riders lying in the road.
A photo posted by WMUR-TV showed motorcycles and wreckage scattered across the highway and a truck on the shoulder in flames.The crash created a chaotic scene in the town of about 300 people.
"There was debris everywhere," said Miranda Thompson, 21, of Manchester, who was several cars back and recalled seeing a truck in flames on the side of the highway and six motorcycles.
"People were in the grass," she said. "There were people putting tourniquets on people, trying to make sure they didn't move."