The offer was made to the mother and father of Jean Charles de Menezes by a senior Metropolitan Police commander during a hurried meeting arranged eight days after the electrician was shot dead at Stockwell tube station.
His grieving parents, Maria de Menezes, 59, and Matozinhos, 66, claim they were pressurised into agreeing to the meeting with Deputy Assistant Commissioner John Yates at their home in the remote town of Gonzaga, with less than a day's notice.
Jean Charles's brother, Giovani, told The Mail on Sunday: "They thought we were poor people, stupid people. We may be poor but we are not that stupid. We will not exchange money for my brother's life - but we will punish them."
However, the money was offered as part of a larger financial package prepared by the Metropolitan Police to fund the family's funeral and travel expenses. The force insists it was not trying to buy the family's silence, but making a genuine offer of help.
The typed letter, written in English, also promised to pay for his body to be flown home, air tickets for close relatives, the funeral costs and some legal expenses for the family. The £15,000 offer, the letter stressed, was an ex gratia payment "paid without any consideration of legal liability or responsibility" - including possible legal action against the force. However, newspaper claims yesterday that the force had offered $1m (£560,000) were dismissed as wholly untrue by the Met.
The family felt insulted by the £15,000 offer, Mrs de Menezes said. "I thought it was disgusting for this policeman to be talking about money when my son was only just buried. I did not like having to sit near such a man."
Although the police letter advised them to get advice from the family's lawyers in Britain, the de Menezes's claim their requests to postpone the meeting until their lawyer could get to them were turned down by Mr Yates.
"We do not want money in exchange for Jean's life, but we want to punish them - so we want a lot of money. We are also concentrating on making sure these policemen go to prison," said Giovani.
The incident adds to the family's wider complaints about their treatment by the police and is consistent with their repeated demands for judicial action against the Metropolitan Police.
The family's campaigners, Justice4Jean, allege that close relatives who flew into Britain on Sunday 24 July, two days after his killing, were given a hotel on the outskirts of London and had the phone to their room cut off.
Their contacts with the police were restricted to two family liaison officers, and they were refused meetings with senior force commanders. Family members in London and Brazil also protest that their requests for detailed information were turned down.
However, his relatives did discover - from remarks to them by their police liaison officer soon after they arrived in London - that CCTV footage from Stockwell station had shown Jean Charles walking calmly into the station.
In contrast to widely circulated eyewitness claims that he had been seen running into the ticket hall and had vaulted the ticket barriers, the family were unofficially told that he had used his Oyster travel pass. And, they were told, he was dressed in a lightweight denim jacket, not the bulky coat which some witnesses claimed.
Those disclosures were confirmed last week when a confidential dossier compiled by the Independent Police Complaints Commission (IPCC) was leaked to ITV News. Those papers also revealed that Jean Charles had neither run from police nor resisted arrest, before being seized by an undercover officer and then shot dead at close range.
His mother said: "Now I know the real truth about why they killed him, I am so hurt I can't sleep. First they killed my son, now they are killing me. I take sleeping pills but still I wake in the night shaking."
Her son Giovani added: "When Jean came home in his coffin, they had bandaged the top of his head. My mother screamed and screamed. Why did they have to use this many bullets? Was it revenge because they thought he was one of the bombers?"
The family's lawyers say his parents and close relatives remain deeply unhappy about the Met's claims that it is unable to answer questions because the shooting is now being investigated by the IPCC.
According to Gareth Peirce, their London-based solicitor, this "reticence" is in stark contrast to the police's mistaken claims on the day of the shooting that Jean Charles was "directly linked" to the terror investigation. "We express incredulity that senior police officers would have made extravagant claims from the outset without first informing themselves of the true facts. To have done anything else was negligent in the extreme," Ms Peirce said.Reuse content