The family of a British aid worker killed by an Israeli strike in Gaza in April on Wednesday called for an independent investigation into his death.
James Kirby, from Bristol in southwest England, was one of seven people killed in a strike on a World Central Kitchen food convoy.
The deaths drew the ire of world leaders and Israel called the strike a "grave mistake".
Former serviceman Kirby and two other Britons killed were part of the security team accompanying aid workers employed by the US-based charity.
Speaking on behalf of his family ahead of a memorial service for Kirby, his cousin Louise Kirby called for a "proper, independent inquiry into this attack on innocent aid workers".
"Whilst we have had much support, we are still struggling to find answers and accountability for what happened," she said in a statement Wednesday.
Kirby said the family was "surprised" that they had not had any contact from Israel's ambassador to the UK or any Israeli official.
"Any family of a loved one who has been killed needs closure. We need to understand how this disaster could have happened," she said.
"But this is not just about us. This is about how Britain looks after its own citizens and their families, when a British citizen has been unlawfully killed by another state."
A UK government spokesperson said that "the death of James and his fellow aid workers was horrific and our thoughts remain with their families".
"Israel must guarantee the protection of aid workers, and ensure a tragedy like this cannot happen again," the spokesperson added.
Last week, US-based aid group Anera said that four people accompanying its convoy in Gaza were killed in an Israeli air strike. Israel said its military had struck armed assailants.
The World Food Programme also said it was pausing movement of its staff in Gaza "until further notice" after one of its vehicles was struck by gunfire at an Israeli military checkpoint.
In May, the United Nations said an Indian member of its security services was killed and another wounded when a UN vehicle was struck on the way to a hospital in Rafah.
The Israeli embassy in the UK has been contacted for a comment.
