Judgement has been reserved over an attempt to challenge the decision not to prosecute police officers over the death of Jean Charles de Menezes.
The Menezes family have campaigned for transparency
A decision is expected by Christmas. The Brazilian was shot after police mistook him for a suicide bomber on a London Tube train on 22 July last year.
His family's QC told the High Court the failure to prosecute officers over his death violated their human rights.
The Metropolitan Police faces a trial under health and safety laws.
Fifteen officers were investigated, but the Crown Prosecution Service (CPS) decided there was "insufficient evidence" to prosecute.
The High Court is being asked to quash a decision not to prosecute any individuals for murder, gross negligence, manslaughter or any other offence.
'Lack of reasoning'
On Tuesday, Michael Mansfield QC, who appeared for the family, told the court in London that if no individual was held personally accountable for his death "the rule of law is undermined".
He also argued the law had been misapplied and there had been "lack of reasoning as well as misdirections".
"No reasonable prosecutor could have come to these conclusions," he said.
Mr Mansfield said the decision not to prosecute was a violation of the family's rights under Article 2 of the European Convention on Human Rights, which protected the right to life and also required an adequate trial or inquiry to "deter life-endangering conduct in future".
The Menezes family's lawyers have said the handling of the case has "the appearance of a stitch-up" and amounted to a breach of his family's human rights.
A spokesman for the Jean Charles de Menezes family campaign said: "The Met's organisational failure and flawed tactics led to Jean's death.
"But within the Met, individuals devised the shoot-to-kill policy, individuals ordered Jean's killing and individuals shot the seven bullets in his head.
"We are bringing this challenge because we believe that individuals should bear responsibility for this crime.
"Otherwise a message is sent out that police officers can kill with impunity."
The force faces charges of failing to provide for the health, safety and welfare of Mr Menezes, 27, on the day he was shot seven times in the head at Stockwell Tube station.