New Hampshire State Police say autopsies show the four men who died in a car crash were killed instantly and that speed was a contributing factor.

Police also said Tuesday that only one person, the driver, Jeffrey Levesque, was wearing a seatbelt.

Their mangled car was found Sunday in the woods in Manchester, off one of the state's busiest stretches of highway. The four were last seen at a restaurant and bar around 1 a.m. Saturday.

Police say toxicology reports are being conducted.

The victims were three childhood friends — 24-year-old Levesque and Alex DeFreitas, both of Londonderry; 25-year-old Chase Abreu of Pelham — and Levesque's friend and co-worker, 25-year-old Jesse Pena of Lowell, Mass.