Two more people are now in custody related to a theft at Heathrow Airport in which 21 people were injured by what is thought to be pepper spray, according to police.
A man, 24, was arrested in the Lambeth area for suspected theft 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 come after a probe into an attack at the multi-storey car park at Terminal 3 this past Sunday. Before the incident, two women had stolen from them their luggage after getting out of a car park lift.
A toddler aged three was one of the those hurt during the incident. Five people went to hospital for medical care and were later discharged.
Officers arrested a man in his thirties on suspicion of robbery and assault near the location. He has since been released under investigation while inquiries continue.
Authorities were called at about 8:10 in the morning GMT after reports came in regarding several people injured by an irritating chemical thought to be pepper spray.
The attack - an event that authorities stated was isolated and not being treated as an act of terror - caused train delays and the partial closure of the main airport tunnel and the Terminal 3 car park briefly.
