BEECH GROVE, Ind. -- A coworker of a woman who was stabbed to death in an attack that happened while two children slept nearby was arrested in connection with the crime, police said.

Officers were called to the Beech Meadow Apartments at 144 Diplomat Court in Beech Grove just after 2 a.m., 6News' Derrik Thomas reported.

Investigators said Mallory Olhausen, 25, and her boyfriend, Jonathon Tolan, 21, who was visiting at the time, were both stabbed.

Olhausen was pronounced dead at the scene, while Tolan was taken to Wishard Memorial Hospital in serious condition.

Olhausen's two children were sleeping in the home at the time but were unharmed, police said.

Investigators arrested Malcolm Williams, 20, who worked with both Olhausen and Tolan at the Beech Grove Walmart store, on Tuesday.

"We know they were all involved in a work relationship. The two victims were boyfriend and girlfriend. (We're) still looking for a connection of Williams, other than coworker status," said Beech Grove Police Chief Rich Witmer.

Neighbors said they heard the commotion early Tuesday morning.

"I heard screaming," said 10-year-old Clayton Miller. "'Stop, stop,' someone was screaming. I thought it was the TV."

Miller was cleaning blood off the family's mailbox as police continued to process the crime scene.

"My little boy is out here cleaning up blood. It's not right," said his father, Joe Miller. "I hope they find the person who did it."

Original reports that three people had been stabbed were incorrect.

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