FARMINGTON — Excessive speed caused a tractor-trailer driver to lose control of his 18-wheeler and crash into a YMCA minivan, killing a 12-year-old girl from Connecticut last month, police said Monday.

The tractor-trailer was going at least 11 mph over the speed limit on a sharp, curving yield entrance to Route 2 in Farmington before the crash, according to Farmington Police Officer Wayne Drake.

The tractor-trailer veered across the center line and hit the minivan, which was stopped in traffic on the other side of the road. Tess Meisel, of Westport, Conn., was killed when the truck crushed the rear seats where she was sitting.

“Speed was a factor and pretty much the only factor in causing the crash,” Drake said.

The investigation findings will be submitted today to the Franklin County District Attorney’s Office, which has stated it will review the crash report to determine whether to pursue criminal charges, said Drake.

Charles Willey, 53, of Dexter, who was driving the tractor-trailer owned by Linkletter Trucking of Athens, did not have a criminal background, said Drake, the primary investigator.

Distraction, mechanical failure, alcohol or drugs did not play a role in the crash, Drake said.

“(Willey) seemed to have a clean background, and I believe he was a safe driver,” Drake said. “It was purely bad judgment.”

The trucking company did not reply to a request for comment about the investigation Monday.

State police conducted a reconstruction of the crash to determine the speed of the tractor-trailer just before it crushed the rear of the YMCA minivan carrying young campers the morning of Aug. 17, said Drake.

The tractor-trailer had just crossed the Sandy River on Route 4 and turned right, heading south, onto Route 2 when it crossed the centerline and hit the van, according to police reports.

The tractor-trailer then tipped onto its side, spilling its load of sawdust.

Drake said the tractor-trailer’s exact speed at the time of the crash is still unclear. Skid marks left by its tires and other evidence do not provide a definitive speed, he said

The reconstruction determined the tractor-trailer had to be traveling at least 41.44 mph to tip onto its side, Drake said. The posted speed limit on the yield entrance is 30 mph, and there are other traffic rules tied to slowing down for the yield, he said.

Drake has been contacted by attorneys representing Meisel’s estate about possible litigation, he said, declining to give other details about possible legal filings.

There have been no criminal complaints or civil lawsuits filed in connection with Meisel’s death, according to a spokeswoman at the Franklin County Superior Court in Farmington.

Suzanne Tanner, the girl’s mother, declined to comment Monday on the investigation.

The minivan was traveling from Acadia National Park to a park in Vermont, according to police reports.

Morning Sentinel Staff Writer David Robinson can be contacted at 861-9287 or at: drobinson@centralmaine.com