Two more people are now in custody related to a robbery at Heathrow Airport in which 21 people sustained injuries by what is thought to be an irritant spray, according to police.
A man, 24, was arrested 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 remain in custody, the force said.
These detentions come after a probe into an attack at the multi-storey car park at Heathrow's Terminal 3 on Sunday. Prior to the incident, a pair of female travelers had stolen from them their luggage upon exiting a car park lift.
A toddler aged three was among the injured during the incident. A total of five individuals went to hospital for treatment and were later discharged.
Officers arrested a man in his thirties on suspicion of robbery and assault close to the scene. He has since been released under investigation while inquiries continue.
Authorities were alerted at approximately 8:10 in the morning GMT following reports of a number of people hurt by a noxious substance believed to be pepper spray.
The attack - which authorities stated was isolated and not being treated as terrorism - resulted in delays to rail services and the temporary shutdown of the Central Terminal Area tunnel and the T3 parking facility briefly.