The Manchester Arena bomber left a note to his landlord apologising for “any mess” he made, a court has heard.
Jurors were shown a scribbled apology written by Salman Abedi before he carried out the fatal blast, killing 22 people and injuring hundreds more.
Hashem Abedi, 22, is on trial at the Old Bailey, accused of helping his brother plan the attack at the end of the Ariana Grande concert.
He denies 22 murders, attempted murder, and conspiring to cause explosions.
Salman detonated a homemade device packed with shrapnel as 359 people milled around the arena foyer at 22:31 BST on 22 May, 2017 – one minute after the concert ended.
Before carrying out the terrorist attack, he left a note inside an apartment in Granby House in Manchester city centre.
It read: “Sorry if there is anything missing in the apartment or any mess made, the extra 150 [pounds] and the rest of the week’s rent can hopefully cover it. ‘Sam’.”
Salman rented the one-bedroom property, agreeing to pay £750 for a two-week short-term stay, jurors previously heard.
But four days into the let, he was seen on CCTV leaving the flat and heading to Manchester Arena, where he detonated his suicide bomb.
Landlord Ruth Bain told police her subsequent attempts to contact the new, short-term tenant were unsuccessful. She later recognised his face from media coverage of the bombing suspect.
Photographs taken during searches of the Granby House flat and the family home in Fallowfield in the days after the bombing showed discarded oil cans, residue from bomb-making chemicals, and various nuts and bolts, the court heard.
Officers also discovered items at the flat including scrapings from match sticks, various bits of wire, black tape, a serrated edge saw, and a roll of clear acetate, prosecutors said.
The trial continues.