IMPERIAL, Mo. (AP) -- St. Louis County police believe a 2-year-old boy found dead early Thursday near a Jefferson County school was killed by his mother's boyfriend.

The 22-year-old man has been arrested, and authorities were seeking warrants to charge him with first-degree murder, police spokeswoman Tracy Panus said.

The victim was identified as Adin Choi. Police believe the boy was killed at a motel in the Woodson Terrace area of St. Louis County.

A lengthy search for the child began Wednesday afternoon. Police were initially told the child had wandered off from the man.

Adin's body was found near a school in Imperial.