Why did police spy on Jean Charles de Menezes' grieving family?

Undercover officers spied on the grieving relatives of Jean Charles de Menezes and at least 11 other families who were campaigning for justice against the Metropolitan Police, a report is expected to reveal today.

What is the report looking into?

The report is looking into the behaviour of the Special Demonstrations Squad (SDS), an elite unit of the Met Police that was disbanded in 2008. Derbyshire Constabulary Chief Constable Mick Creedon, who is running the internal investigation into the SDS, said yesterday that it would criticise police for keeping information gathered by undercover officers that "served no purpose in preventing crime or disorder".

What will it say?

According to Channel 4 News, at least 12 families who appear in the reports and notes of SDS officers have been contacted by the Metropolitan Police. That figure includes the family of Mr De Menezes, the electrician shot dead by anti-terror police who mistook him for a suicide bomber in 2005.

It also includes the families of Cherry Groce and Ricky Reel. Ms Groce was shot and paralysed by police in 1985, and the incident sparked the Brixton riots. Mr Reel was 20 when he vanished during a night out in London in 1997 shortly after being racially abused by two white men. His body was found in the River Thames. Mr Reel's mother Sukhdev, who has publicly campaigned for an inquiry into his death, said she felt "stripped of my dignity" and "really angry" at the claims.

This isn’t the first SDS controversy, is it?

Mr Creedon has already examined claims that the SDS used the identities of dead children when undercover. He found that out of 106 secret identities used by the SDS, 42 were either “confirmed or highly likely” to be from dead children. The Guardian has also reported that undercover officers from the SDS "routinely" entered into sexual relationships with the activists they were investigating. Today's report also comes months after it was found the family of Stephen Lawrence was spied on by an SDS officer.

When is the full report out?

The report will be released at midday.