Louis de Zoysa: Suspect in killing of police sergeant from middle-class London family

The man suspected of shooting dead Sergeant Matt Ratana inside a police station, has been named as Louis de Zoysa, the eldest of five children from a middle-class south London family.

Born in Croydon, the 23-year-old Catholic former churchgoer is believed to be severely autistic.

His mother, Elizabeth, 55, is a legally trained Dutch-to-English translator who once stood as a candidate for the Green Party in local council elections.

His Sri-Lankan born father, Channa, also, 55, is the director of an events management company who lists bee-keeping, playing guitar and cycling among his interests.

The family live in a smart terraced house in Norbury, south London, which remained cordoned off on Sunday day by police who have been carrying out forensic searches.

Mr de Zoysa has two younger brothers, one of whom, John, 21, is studying for a masters in engineering at Oxford University and is the secretary of the university's Sri Lankan society.

He also has two sisters, one of whom has done several charity bike rides in aid of the Sri Lankan Christian Association. All five children attended local Catholic schools.

A childhood friend of Mr de Zoysa said he had been a "troubled kid", and the police had been regular visitors to the family home down the years.

Scotland Yard confirmed they were conducting searches at the family home as well as at another rural location in Banstead, Surrey.

Residents living close to the scene of the second search were woken at around 5am to the sound of a large explosion, believed to be armed officers forcing entry into what has been described as a former Second World War bomb storage unit.

Locals claimed they had noticed white vans visiting the property in recent months, but assumed they were security guards.

Tony Dakin, an artist who lives across the road, explained: "It's a Second World War bomb storage site ... with six to eight storage units."

Another neighbour, Colin Sutherland, said: "We assumed security was living in one of them. People go up and down in white vans occasionally. We didn't know they were ... we thought they were just security."

Another resident, who asked not to be named, said: "A couple of young men were always sort of walking up and down. I am not sure how they found out about that place to rent. There were lots of comings and goings with vans over the last six months."

She said the men who visited the site never made eye contact with anyone who spoke to them. Meanwhile, Scotland Yard confirmed that a man had been arrested in the Norwich area in the early hours of the morning on suspicion of supplying a firearm.

Norwich is an area which has problems with London-based county lines gangs, who target vulnerable people in order to sell heroin and crack cocaine.

Mr de Zoysa was arrested not far from his family home just after 1.30am on Friday after officers patrolling in the Norbury area carried out a routine stop and search and allegedly found two rounds of ammunition and cannabis resin.

After calling for backup, the officers handcuffed the suspect behind his back and transported him to the nearby Croydon Custody Centre.

The suspect was about to be searched by an officer with a metal detector when it is alleged that he retrieved a revolver that was hidden about his person and opened fire five times, hitting Mr Ratana in the chest.

The Independent Office for Police Conduct is carrying out an investigation into the incident and it is expected to focus on why the gun was not found during the initial stop and search.

Ken Marsh, the chair of the Metropolitan Police Federation, has said officers do not have the powers to carry out intimate searches in public and suggested that any review looks at whether they should have portable metal detectors.

"There has to be an element of protection towards us," said Mr Marsh. "It's not dignified. There has to be a balancing back to us as human beings."

He said while hand-held metal detectors could be helpful, they would bring their own problems.

Mr de Zoysa, who was also hit by a bullet, remains in hospital in a critical condition.