An additional two individuals are now in custody related to a theft at London's Heathrow Airport in which 21 people sustained injuries by what is thought to be an irritant spray, according to police.
A 24-year-old man, was taken into custody in Lambeth for suspected robbery and assault and a 23-year-old woman was arrested on suspicion of conspiring to commit a robbery. They both are still being held, the force said.
These detentions follow a probe into an assault at the multi-storey car park at Heathrow's Terminal 3 this past Sunday. Before the incident, two women were robbed of their luggage after getting out of a car park lift.
A three-year-old girl was one of the injured in the event. A total of five individuals went to hospital for medical care and have since been discharged.
Officers detained a 31-year-old man on suspicion of robbery and assault close to the location. He was subsequently released under investigation as the investigation proceeds.
Police were called at about 8:10 in the morning GMT following reports of several people injured by an irritating chemical thought to be an irritant spray.
The assault - an event that authorities stated was isolated and not being treated as terrorism - caused delays to rail services and the partial closure of the Central Terminal Area tunnel and the Terminal 3 parking facility for a short time.
