An Indianapolis woman was killed in an incident on Interstate 74 in Decatur County early Tuesday morning.

Decatur County Sheriff Greg Allen says that deputies were initially called to the 140 mile marker of eastbound I-74 on a report of a fight. When they arrived at about 1:20 a.m., deputies reported finding the body of 54-year-old Deborah Dillard in the driving lane of the interstate.

The driver of the semi, Gary L. Gregory, 69, of Rensselar, IN, reportedly told investigators that he was traveling east on the interstate when he saw a woman running from the south side of the road, into the path of his semi. According to the report, Gregory said that he tried to drive into the median to avoid hitting the woman, but he was unable to do so. Sheriff Allen says that Dillard was struck by the right-front corner of the semi. He says that she was taken to Decatur County Memorial Hospital, where she died.

Sheriff Allen says that his department’s initial investigation revealed that Dillard was driving a vehicle on westbound I-74 when she pulled over into the emergency lane due to “an altercation with a female passenger.” He says that, at some point, both women ran across the eastbound lanes of the Interstate, leading to the accident, which closed down the eastbound lanes of I-74 for approximately two hours. The passenger’s identity has not been released.

Allen says that the investigation is ongoing.