Exclusive: Did police spy on family of cells death victim Christopher Alder?

An internal review by Humberside Police found “information to suggest” that Miss Alder and an unnamed party were placed under surveillance during the inquest in August 2000.

The force referred itself to the Independent Police Complaints Commission (IPCC), which is now investigating.

An IPCC spokesman said: “The IPCC received a referral from Humberside Police concerning Janet Alder, the sister of Christopher Alder who died in police custody in Hull in 1998, and another person.

“According to Humberside Police there is information to suggest that Ms Alder and the other party were the subjects of improper surveillance.

“The IPCC has determined that an independent investigation should be carried out to establish what surveillance took place and the reasons for it. The IPCC has contacted Ms Alder and the other party to offer a meeting to discuss the referral.”

Speaking exclusively to the Yorkshire Post, Miss Alder said: “I had to send my son away to his dad because I thought I was being followed - they don’t understand the impact it has.

“All you are doing is asking for the truth (at the inquest) and they treat you like enemies of the state.

“It’s disgusting. I want to know who’s done it, who’s given them the authority, and for what reason.”

A spokeswoman for Humberside Police said: “Following an internal review, conducted in the light of interest in covert policing tactics, Humberside Police has chosen to refer to the IPCC an operation conducted a number of years ago.

“This means that Humberside Police will be unable to comment further until such time as the IPCC has concluded an investigation.”

Mr Alder, 37, a former paratrooper, died on the floor of the custody suite in Queens Gardens police station in Hull on April 1, 1998.

The inquest jury found he had been unlawfully killed.

His body was found in a morgue 11 years after he was supposed to have been buried.