DAYTON (AP) — A coroner’s office says a 6-year-old boy pulled from a swimming pool last week and hospitalized in southwestern Ohio has died.

The Montgomery County Coroner’s Office says Niguel Hamilton died Sunday night. The cause of death wasn’t immediately released.

Medics had transported the boy to a hospital after he was pulled from an indoor pool at Dayton’s Lohrey Recreation Center on Thursday.

The city has said in a statement that a thorough investigation is being conducted. A detective from the Dayton Police Department also has been assigned to the investigation.

No other details were immediately available Monday.

The child’s grandfather has said Niguel was at the pool for swimming lessons.