The fingerprints of Hashem Abedi were discovered on a tin can that has been linked to the Manchester Arena bomb, a court has heard.
The discovery was made after police found various crushed-up metal tins in the garden of the Abedi family home, jurors were told.
Hashem Abedi, 22, is on trial at the Old Bailey, accused of helping his brother Salman plan the bomb attack.
He denies 22 murders, attempted murder and conspiring to cause explosions.
The court heard how a piece of metal found at the scene was linked to a vegetable oil tin with the alleged plotter's fingerprints on it.
Police found the crushed up tins in the garden of the Elsmore Road home in Manchester with prints from both brothers on them, the court heard.
A piece of a Consumer's Pride cooking oil tin was found to have 10 finger and palm prints belonging to Hashem on it, jurors were told.
Six parts of the same tin were recovered from an address in Granby Row, Manchester, where Salman allegedly assembled the bomb.
Fingerprint expert Philip Balduini told jurors he had identified four of Hashem's prints on the scraps, which had been rolled up and left in a blue plastic bag.
Hashem had hoarded assorted metal cans in his garden, taken from a takeaway restaurant where he worked, jurors were previously told.
While none of these were found in the construction of the bomb, it was alleged the piece from the cut-up Consumer's Pride tin was in Salman's rucksack.
The court has previously heard how Salman detonated a homemade device packed with shrapnel in the arena foyer at an Ariana Grande concert on 22 May 2017 ended, killing 22 people.