Director of Public Prosecutions Keir Starmer QC approved a decision not to prosecute any police officers over the shooting. Menezes' cousin Vivian Figueiredo said the Crown Prosecution Service (CPS) move was "deeply upsetting."
She said the family will turn their energy to lobbying Parliament on the laws surrounding police accountability.
Ms Figueiredo observed: "We are all in shock and simply cannot understand how the deliberate killing of an innocent man and an attempt by the Metropolitan police to cover it up does not result in a criminal offense.
"We condemn the CPS decision and reject the logic of their argument. The inquest put the truth out there for all the public to see, but the authorities want us to forget the truth to stop us getting justice. But we will never forget."
Prosecutors conducted an extensive review of the evidence presented at the three-month inquest into his death last year. But they found insufficient evidence to pursue the officers who pulled the trigger or those who oversaw the operation for manslaughter or gross negligence.
Menezes was shot dead by two marksmen after boarding a train at Stockwell Tube Station on July 22, 2005, after he was mistaken for suicide bomber Hussain Osman. The incident happened a few days after the terrorist bombing of London.
An inquest jury returned an open verdict last December after hearing three months of evidence. Coroner Sir Michael Wright was criticized in December for ruling out unlawful killing as a possible verdict
Mercopress