A man has been arrested on suspicion of murdering a police officer who was shot dead at Croydon custody centre.
New Zealand-born Sgt Matiu Ratana, 54, known as Matt, was shot in the chest as a handcuffed suspect was being taken into custody on 25 September.
Louis De Zoysa, 23, also suffered a gunshot wound and was taken to hospital in a critical condition.
The Met Police said he had since “stabilised” and was considered fit to be arrested on Friday.
Mr De Zoysa remains in hospital with “life-changing injuries” and detectives will consult with doctors and legal advisers before they begin interviewing him.
The Met Police Commissioner, Cressida Dick, said of the arrest: “It’s an important milestone and hopefully it brings some tiny comfort to Matt’s partner Su, Matt’s wider family and everyone who has been affected.
“The investigation is moving on into a dreadful, dreadful homicide.”
An inquest at South London Coroner’s Court in October heard Sgt Ratana died from a gunshot wound to the chest.
No police firearms were discharged in the shooting.
Earlier this month, a funeral for the long-serving officer was held at Shoreham-by-Sea, West Sussex, and live streamed on the internet so his family, friends and colleagues around the world could attend.
Specialist family liaison officers are supporting Sgt Ratana’s family, who have been informed of the arrest.