The sister of two brothers arrested during an anti-terror raid on their east London home said there was nothing "sinister" about the thousands of pounds in cash which was found in a locked suitcase by police.

The armed officers, who were looking for evidence of a chemical bomb at the property in east London, found £38,000 in a suitcase in the basement next door.

Humeya Kalam said the cash came primarily from the rental income of the house next door to where she lives with her brothers Mohammed Abdul Kahar, who was shot during the operation, and Abul Koyair, 20, in Forest Gate.

Ms Kalam said she had told police just two hours after they stormed the house in the early hours of the morning on June 2 that they would find a "substantial" amount of cash in a suitcase in the basement of number 48, which she owns.

However, it was "neither sinister nor unexplained", she insisted. She said the money had been held there by her mother for "safe keeping" during the four years she had owned the property.

"My mother has never felt it right to keep this money in a bank account, or to hold savings in a bank; Islam prohibits the keeping of money in circumstances where interest is earned or where it is paid," Ms Kalam said.

"My mother has always held our savings in this way; in the same way the money was kept by her for me to buy number 48. Now, in turn, I am providing my income for my mother to keep in the same way."

She said her brothers both contributed from their wages every month to the money held by her mother.

They had all explained to police that this was the sum total of their collective contributions, she said.

The money, said to be in £50 notes, was found during a detailed search of the house in Forest Gate that included probes being inserted into the walls and ceilings to look for any cavities, the back garden being dug up and plaster board removed.

The brothers were held for a week under anti-terror legislation at a high security police station following the dawn raid on their house.

They were freed without charge and earlier this week the pair spoke for the first time about their ordeal and demanded that those who ordered the raid should be brought to justice.

Mr Kahar, 23, who was shot in the chest, described the moment he was shot: "I said, ‘Please, I can’t breathe’, and they just kicked me in the face and kept saying, ‘Shut the f*** up’. I thought they were going to shoot me again or my brother.

"I feel ashamed for asking them to spare my life. I still didn't know they were police. One of the officers grabbed my left foot and dragged me down the stairs, my head was banging on the stairs."

Scotland Yard has apologised for the "hurt" caused to the two men.

Times Recommends

• The playboy and the Tory party leader
• Bin Laden's family tree is impenetrable jungle
• Paul McCartney