YARMOUTH, Mass. — A toddler who was found unresponsive in his crib and later died was the son of substance abusers, had several medical conditions and had been placed in the care of relatives, officials said Thursday.

Police and fire officials responded to the family’s Yarmouth home on Thursday morning after receiving a report of an unresponsive child.

Despite rescue efforts, the 23-month-old boy was declared dead at Cape Cod Hospital.

Cape and Islands District Attorney Michael O’Keefe said the state Department of Children and Families was involved with the boy since birth because his parents had substance abuse issues.

The department recently has been heavily criticized over the case of a 5-year-old Fitchburg boy who has been missing for months and is feared dead.

O’Keefe said the Yarmouth boy was being cared for by a couple and was being seen by a social services agency that dealt with developmental delays. He said the boy was reported to be “well” during the most recent visit on Monday.

He said the boy also was being seen by another agency that focused on emotional issues.

A preliminary investigation did not show significant trauma to the boy, O’Keefe said.

DCF said the boy was briefly placed in a foster home but was removed last year by a judge over the agency’s objections.