A young boy picked up a pipe bomb after it exploded in Londonderry, police have said.
The explosive device was found in a garden at Curlew Way in the Clooney area of Derry's Waterside on Tuesday.
The boy lifted the remains of the bomb at about 18:00 BST and police were notified about three hours later.
The people who placed the pipe bomb were "completely reckless", said the Police Service of Northern Ireland's (PSNI) Det Insp Michael Winters.
"While this was not a live device, the fact a young boy found it and lifted it shows the blatant disregard by those responsible for leaving it there," he said.
The police investigation is at an early stage, he added.
"However, it appears at this time the device had detonated prior to it being lifted by the young boy."
The detective appealed for anyone with information to contact police.