Two more people are now in custody in connection with a theft at London's Heathrow Airport where 21 people sustained injuries by what is thought to be pepper spray, according to police.
A man, 24, was arrested in the Lambeth area on suspicion of robbery and assault and a woman, 23 was detained for suspected conspiring to commit a robbery. They both are still being held, the force said.
The arrests come after an investigation into an assault at the multi-level parking garage at Terminal 3 on Sunday. Before the incident, two women had stolen from them their suitcases upon exiting 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 treatment and were later discharged.
Police detained a man in his thirties for suspected robbery and assault near the scene. He has since been released under investigation while inquiries continue.
Police were alerted at about 08:10 GMT following reports of a number of individuals hurt by a noxious substance believed to be an irritant spray.
The attack - which authorities stated was a standalone incident and not considered an act of terror - resulted in delays to rail services and the temporary shutdown of the main airport tunnel and the Terminal 3 parking facility briefly.
