Two police officers are to face gross misconduct hearings after it was found surveillance was carried out on the sister of a man who died in custody.
Former paratrooper Christopher Alder, 37, died in Hull in 1998. An inquest found he died unlawfully.
His sister, Janet Alder, was placed under surveillance in 2000.
The Independent Police Complaints Commission (IPCC) said it "found evidence of a case to answer" for two Humberside Police detective sergeants.
This comes two years after the Crown Prosecution Service (CPS) said there would be no prosecutions for misconduct because of insufficient evidence.
IPCC Commissioner Cindy Butts said its decision was "not taken lightly".
"Taking into account the serious and sensitive nature of the allegations and the weight of the evidence presented to me, I felt it was essential for public confidence that the officers concerned account for their actions," she said.
In a statement, the IPCC said: "Humberside Police did not initially share the IPCC's view that the two officers should face a gross misconduct hearing."
It said the force now accepted the decision after Ms Butts wrote to the organisation.
Humberside Police confirmed it had received the IPCC's instruction.
In 2006, the IPCC found four police officers were guilty of the "most serious neglect of duty" over the death of the ex-paratrooper.
Mr Alder died while lying face down and unconscious in a pool of blood in a police custody suite, as a group of officers stood chatting nearby.
Five officers were cleared of manslaughter and misconduct in 2002 over his death.
The surveillance came to light when a serving Humberside Police officer told superiors of the operation after the home secretary asked all police forces to check for evidence of surveillance relating to inquiries into the murder of teenager Stephen Lawrence in 1993.
It was investigated by the IPCC following a referral by the force.
The IPCC said it would "consider publishing its findings in full, once all proceedings have been concluded".
A date for the misconduct hearings is yet to be confirmed.