An additional two individuals are now in custody related to a theft at Heathrow Airport where 21 people were injured by a substance believed to be an irritant spray, according to police.
A man, 24, was arrested in Lambeth for suspected robbery and assault and a woman, 23 was detained for suspected conspiracy to commit robbery. Both individuals are still being held, the force said.
These detentions follow a probe into an attack at the multi-storey car park at Heathrow's Terminal 3 on Sunday. Before the incident, two women were robbed of their luggage upon exiting a car park lift.
A three-year-old girl was among the those hurt during the incident. Five people were taken to the hospital for medical care and were later discharged.
Police detained a 31-year-old man on suspicion of robbery and assault near the scene. He has since been released under investigation while inquiries continue.
Authorities were called at approximately 08:10 GMT following reports of a number of people hurt by an irritating chemical believed to be pepper spray.
The attack - an event that authorities stated was a standalone incident and not considered terrorism - resulted in train delays and the partial closure of the Central Terminal Area tunnel and the Terminal 3 parking facility for a short time.
