BELLEFONTAINE NEIGHBORS, Mo. (AP) — Authorities say a relative of a slain 3-year-old has been arrested on suspicion of killing the teenager accused of unintentionally shooting the toddler.

The St. Louis Post-Dispatch reports that police say 17-year-old Kameron Harvey was shot on Oct. 4 while riding his bike in Bellefontaine Neighbors, a city just north of St. Louis.

Harvey was on house arrest while awaiting his manslaughter trial in the December 2015 death of the toddler, Xavier “Zae” Robinson.

Authorities say the shooting happened while Harvey was playing with the laser site on a handgun inside a home. Harvey was a friend of the family and 15 at the time. His case was being prosecuted in adult court.

Police say two 17-year-olds were arrested about an hour after Harvey was killed. Police say at least one is related to the toddler.