A Cartersville couple — on a furlough from mission work in Italy — were on their way home when a tractor-trailer crashed into them Thursday night.

Kyra Karr, 30, died at the scene of the wreck. Her two young children and husband were injured when the tractor-trailer pinned their pickup truck against a guard rail, trapping the family inside, according to police in Bartow County.

The children, ages 2 and 4, were both in stable condition Friday at Children’s Healthcare of Atlanta at Scottish Rite. Reid Karr was in stable condition at WellStar Kennestone Hospital, according to police.

Kyra Karr was a graduate of the University of Georgia and grew up attending Tabernacle Baptist Church in Cartersville, according to IMB, the International Mission Board. The family, appointed as Southern Baptist missionaries in 2009, were about to start their third term of service in Italy after a brief assignment in the United States, according to IMB.

Investigators believe the tractor-trailer driver, identified Friday as Ivan Delgado, was outside of his vehicle conducting a safety inspection when it started to roll, Emerson police told Channel 2 Action News.

Delgado reportedly parked his tractor-trailer at a chemical plant in the 300 block of Joe Frank Harris Parkway or Highway 41 in Emerson — a town near Cartersville. Employees told police the man was acting erratic before the incident happened. Police said Delgado was under the influence of a mind-altering substance at the time of the wreck.

Delgado, 52, of Rome, N.Y., was arrested and charged with DUI, involuntary manslaughter, vehicular homicide and reckless conduct, police said.

“The brakes, the parking brake on the vehicle was either not set or failed causing the vehicle to become unsecured and rolled down the hill, striking the red truck as it was traveling northbound on Highway 41,” Emerson police Chief Stan Bradley said.

Emergency crews worked for about two hours to extricate the family after the 9 p.m. crash. The tractor-trailer spilled hazardous materials onto the highway, slowing the process of removing it, according to a press release sent Friday afternoon.