CANAAN – Police are still trying to unravel the cause of a chain-reaction accident that reportedly injured seven motorcyclists Saturday afternoon.

Not even all the victims had been identified in police information available Sunday. The accident investigation was complicated by members of Hell’s Angels and several other motorcycle clubs removing evidence from the scene, according to Maine State Police Lt. Dale Lancaster.

Rebecca Miller, 40, of Greene was listed in critical condition at Eastern Maine Medical Center in Bangor on Sunday, 24 hours after she and her husband were involved in the collision on Route 23.

According to Lancaster, Miller and her husband, who was not identified, were riding north on Route 23 near the Clinton town line at about 3:55 p.m. when they crested a knoll and met a procession – reportedly up to a mile long – of motorcycles. The procession was connected with an open house at the Canaan clubhouse of Hell’s Angels, Lancaster said. Police were told the bikes were traveling at about 50 mph.

The collision involving Miller’s motorcycle occurred close to the centerline, making it difficult for police to determine who may have been at fault.

“The investigation was exacerbated when the motorcycle groups removed four to five cycles,” Lancaster said. “It appears there was a conscious effort to remove evidence from the scene. When the troopers arrived, their first priority was to prevent any more motorcycles from being removed.”

The procession included gang members from Hell’s Angels, Mountain Men, Saracens, Sons of God and other unidentified groups, the lieutenant said.

An accident reconstruction determined at least five motorcycles were involved in the initial collision. When brake lights came on in the long procession, other rear-end collisions occurred, Lancaster said. He did not have details on the other collisions, but believed no one was seriously injured farther up the line. The other collisions were investigated by the Somerset County Sheriff’s Department, he said.

In the initial collision involving Miller’s motorcycle, seven people were reported injured, but not all were identified in Lancaster’s as yet unfinished report.

According to his information, Miller and David Ireland of Bangor were transferred to EMMC after the accident. Ireland was reported in stable condition there on Sunday afternoon. Other victims were taken to Redington-Fairview General Hospital in Skowhegan and to the Thayer Unit of MaineGeneral Hospital in Waterville, Lancaster said. Others reported injured included Lee Bell of Newport and Robert Pettersen of Portland. No information on Pettersen’s condition was available.

Bell, 36, was identified as one of two people involved in the subsequent collisions. He suffered scrapes and bruises when he “laid his bike down” to avoid a collision with other motorcycles, according to Somerset County Deputy Michael Knight. Gary Stack, 45, of Norway and his passenger, Patricia Dunton, 30, refused medical treatment after Stack also was forced to “lay his bike down” to avoid a collision with Bell’s motorcycle. Both men in the second collision were riding Harley-Davidsons, Knight said.

Details were not available on the report of a third collision.

Eight troopers and four to five Somerset County deputies responded to the report of the accidents, which are still under investigation, according to Lancaster.