LEWISTON – The condition worsened Monday of one of two survivors of Saturday night’s head-on collision in Roxbury on Route 17.

Two people died in the accident.

According to a Central Maine Medical Center spokeswoman in Lewiston, Brandon Gotto is now in critical condition. He was listed in serious condition Sunday night.

Gotto, whom state police say is in his late 20s, was one of two passengers in a 1998 Chevy Blazer driven by Scott Kubic, 30, of Mexico.

The other passenger was Kubic’s wife, Ericka, whose condition was upgraded from stable on Sunday to fair on Monday.

Scott Kubic and Richard Thereau, 37, of Byron, who was driving a 1995 GMC pickup, were both killed when their two trucks collided.

State police spokesman Stephen McCausland said Monday that investigators are trying to determine why Thereau lost control of his truck and crossed the centerline.

The wreck occurred at 7:50 p.m. on Route 17 not far from Coos Canyon in Byron. Thereau was northbound, headed toward Coos Canyon, and the Kubics were southbound when the crash happened.

State Trooper Scott Gosselin, who is handling the crash investigation, was unavailable for comment Monday.