Arkansas police have arrested two people in connection with the deaths of a mother and infant child found dead off the side of an interstate on-ramp on Tuesday morning.

Willie Mott Jr., 43, was initially arrested on an unrelated warrant and later charged with capital murder in the deaths of TeAngela Tate, 27, and her 2-month-old son, Noel Mott, according to KARK. He was also charged with attempted murder of a second child found at the scene, 1 1/2 years old, who has been hospitalized since they were found.

Mott was the father of the infant and was in a relationship with Tate, North Little Rock police said. Detectives believe Mott shot and killed Tate at the apartment where they lived. They have not released information on the cause of the baby’s death or the toddler’s injuries.

Police also arrested Mott’s mother, 70-year-old Diane Mott, charging her with hindering apprehension or prosecution and tampering with physical evidence.

Investigators initially called the case a death investigation after finding the bodies on the Highway 165 on-ramp to Interstate 440 but soon escalated it to a homicide investigation, as CrimeOnline reported.

Both Motts are being held at the Pulaski County Regional Detention Facility, and Willie Mott is set to appear in court Saturday morning.

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[Featured image: Willie Mott Jr. and Diane Mott/Pulaski County Regional Detention Center]