LEWISTON – Mourners turned out Thursday for the first of six funerals over a 36-hour period for victims of a deadly collision early on Dec. 24. Detectives said they planned to step up their investigation after the funerals.

The funeral for Robert Bruce, 19, of Lewiston was held at the Bates College Chapel. He was among four recent high school graduates in a car that slid into the path of another car carrying a Poland couple. Four died at the scene; the other two died at a hospital.

Bruce was a passenger in a car driven by Michael Cournoyer, 20, of Auburn, whose driver’s license had been suspended after a drunken-driving arrest. The other two passengers were Matthew Manley, 18, and Jacob Roy, 20, both of Lewiston.

A funeral was scheduled for Manley on Friday as well as funerals for Steven Walton, 27, and his fiancee, Laura Lynn Caron, 26, both of Poland. A joint service in Auburn was planned for the couple, who were engaged to be married.

Funerals were planned Saturday for Cournoyer and Roy.

The Androscoggin County Sheriff’s Department vowed to step up its criminal investigation after the funerals. Family members and other potential witnesses will be interviewed again, Capt. Ray Lafrance said.

Lafrance declined to speculate on any criminal behavior. Cournoyer and his three passengers were at a party prior to the crash, but police declined to say where the party was held. “No one has been charged,” Lafrance said.

The lead investigator, Detective Sgt. William Gagne, said he’d like to talk to family, friends and potential witnesses who have posted information about the crash on their blogs and Internet bulletin boards.

“It would be nice, if they have enough information to post on their blogs, maybe they could share some of it with police,” he said.

Many details remain to be sorted out. Toxicology tests on both drivers were pending. Even the road condition has not been established conclusively.

Several motorists described the road conditions as slippery, but the Maine Department of Transportation said the area had been salted several hours earlier.

“There’s no indication to us the road had anything but good traction,” said Eric Wright, principal attorney for the Maine Department of Transportation.