Matt Ratana, a 54-year-old custody sergeant who was originally from New Zealand, was shot dead inside a police station in south London. The 23-year-old suspect is then believed to have turned the gun on himself.
"The man's condition, originally critical, has since stabilised and is no longer considered life-threatening. Therefore, on Friday, 13 November he was considered fit to be arrested on suspicion of murder," police said in a statement.
They said the suspect, whom they did not name, remained in hospital and that officers would work with medical and legal experts to determine when he would be fit for interview.
An inquest has heard that Ratana was killed after the suspect, despite being handcuffed behind his back after being arrested, managed to produce a revolver and shot him several times. The inquest has been adjourned while the police carry out their murder inquiry. Police are not treating the murder as terrorism.
