The Associated Press

CAMPBELLSBURG, Ky. - Two people were killed and two others were injured Friday when a tractor-trailer crossed the median of Interstate 71 near Campbellsburg, Kentucky State Police said.

The interstate's southbound lanes were closed, and only one northbound lane was open for about six hours after the 4:30 p.m. crash, police said.

It was not known why the northbound tractor-trailer crossed the median, Trooper Greg Larimore said. That truck hit a southbound tractor-trailer, knocking it over a guardrail and down a hill, he said.

A smaller commercial truck and three passenger vehicles were also involved, Larimore said.

The highway was covered with diesel fuel and oil as well as debris from the wreck.

Larimore said the driver of the northbound tractor-trailer - Ray Pearson, 48, of Telford, Tenn. - was killed in the crash, as was a person traveling in one of the passenger vehicles - Douglas Zielinski, 52, of Bardstown. Zielinski was hit by flying debris, Larimore said.

The driver of the second tractor-trailer - Gilberto Velazquez, 24, of Louisville - was flown to University of Louisville Hospital, where he was in critical but stable condition. William Ragains, 43, of Cincinnati, who was in one of the other vehicles hit by debris, was treated at Baptist Northeast Hospital at La Grange and released, Larimore said.

Police were still trying to determine the cause of the wreck.