The Manchester Arena attacker and his brother used their mother’s bank account to buy tools and equipment to make a bomb, a court has been told.
The Old Bailey heard Samia Abedi’s bank card was used to buy a battery and other items before the 2017 attack.
Mrs Abedi had been receiving tax credits, child and housing benefit totalling £537 a week, even though she left the UK for Libya in October 2016.
Hashem Abedi denies involvement in his brother Salman’s attack.
The jury was told Mrs Abedi’s bank statements showed a series of large cash withdrawals of between £50 and £300 each month in the UK after she left the country.
As well as items from a B&Q superstore, her bank account was also used to pay for an industrial battery from a specialist shop in Salford, the court heard.
Analysis of her documents showed her weekly tax credit and child benefit payments continued until 19 May, the jury was told, three days before the attack which killed 22 people outside an Ariana Grande concert.
Her monthly housing benefit was last paid four days later, on 26 May.
The financial investigation also revealed Salman Abedi, who had dropped out of a business management degree at the University of Salford on 13 January, received a student loan payment of £1,002.54 four days earlier and a further one of £2,258 at the end of the month.
The court was told four cash withdrawals of £700, £710, £790 and £800 were taken from his RBS account on 23 January, before Abedi reported his bank card had been lost.
His Halifax student account card was found in the foyer of the arena after the attack.
Earlier, his brother’s trial heard Salman Abedi went to HMP Altcourse in Liverpool with two other men to meet convicted terrorist Abdalraouf Abdallah on 18 January 2017, four months before the attack.
Abdallah, who was left paralysed after being shot during the 2011 Libyan uprising, was convicted of two counts of preparation of terrorist acts by helping two men enter Syria via Turkey and funding terrorism by sending £2,000 to his own brother.
The jury was told a second meeting was set up for 6 March at the prison, but Salman did not attend.
Hashem Abedi denies 22 counts of murder, one of attempted murder and one of conspiring to cause an explosion.
The trial continues.