PORTLAND, Maine—A couple from Maine being sought in connection with a fatal stabbing in Auburn have been taken into custody in southern Illinois, police said Sunday.

Ryan Muncey, 28, and Alisha Turner, 25, of Lewiston were being held at the Tri-County Jail in Ullin, Ill., on material witness charges, said Maine State Police spokesmen Steve McCausland. State police detectives were planning to travel to Illinois to bring Muncey and Turner back to Maine, where additional charges could be filed.

Muncey and Turner were being sought in connection with the death of 26-year-old Casey Stanley last Wednesday evening.

Casey died of a single stab wound to the chest along a walking trail in Auburn that was known for drinking and fighting in the past. The death has been ruled a homicide.

Turner turned herself into authorities in Jonesboro, Ill., on Saturday night, McCausland said. Muncey was arrested at 7 a.m. Sunday while attempting to climb out a bedroom window at her father’s home in the nearby town of Cobden, Ill.

The couple’s two children, a 2-year-old son and 1-year-old daughter, are being cared for by Turner’s relatives, the spokesman said. Their car has been impounded in Illinois.

Police have not commented on possible motives for the stabbing. The Sun Journal of Lewiston reported that family members had heard rumors that Stanley had owned money to someone.

Muncey and Turner are expected to return to Maine this week pending an extradition hearing in Illinois.