SPOTSYLVANIA COUNTY, Va. — State police are investigating what caused four crashes involving 20 vehicles that closed all lanes of I-95 north Spotsylvania County Sunday morning.

Sgt. Steve Vick with Virginia State Police said the first accident, which involved two cards, happened around 11:43 a.m. at mile marker 120.6 just after the Thornburg exit.

“From that crash Troopers determined that four separate crashes occurred,” Vick said.” The crashes were broken down into one crash with seven vehicles, two separate crashes involving ten vehicles and the last crash involved three vehicles for a total of twenty vehicles.”

Nine people were injured and transported to area hospitals with what did not appear to be life-threatening injuries, according to state police.

VDOT reported that a detour was in place and that traffic was backed up about three miles as of 1:30 p.m.

State police said all lanes of the interstate had reopened by 2:45 p.m.