ST. ALBANS — A 14-year-old boy was killed and three other teenagers were injured Friday afternoon when a pickup truck that was traveling too fast left a road in St. Albans and hit a tree, according to the Somerset County Sheriff’s Office.

The 2013 Toyota Tacoma was carrying an 18-year-old driver and a teen in the cab and two teens in the bed when it traveled off Dudley Brook Road at about 2:15 p.m., according to information released Saturday by Somerset County Chief Deputy Mike Mitchell.

The driver of the pickup, Ethan Milliken of Dexter, lost control of the vehicle before it left the roadway, Mitchell said.

The 14-year-old who died was riding in the bed of the truck. He was taken by ambulance to Northern Light Sebasticook Valley Hospital in Pittsfield, where he was pronounced dead. Officials did not identify the boy, but Mitchell said he was from St. Albans.

Milliken and the two other teens were taken by private vehicle to the Pittsfield hospital, where they were treated for injuries that Mitchell said were not life-threatening. One of the teens was 15 and the other either 14 or 15, Mitchell said later Saturday by telephone.

One of the two teen’s is a brother to Milliken, according to Mitchell, who said the four were friends and near the home of one of the teens when the crash occurred.

None of the four was wearing a seat belt, Mitchell said.

He said excessive speed appears to have been a factor in the crash, but the investigation was continuing, led by Somerset Sheriff’s Deputy Logan Roberts. Slippery conditions from Friday’s rainfall also may have been a factor, he said.

The Maine State Police, firefighters from St. Albans and Hartland and ambulance crews from Newport and the Pittsfield hospital also responded to the crash.