Two more people are now in custody related to a theft at London's Heathrow Airport where 21 people were injured by a substance believed to be an irritant spray, according to law enforcement.
A man, 24, was arrested in the Lambeth area on suspicion of theft and assault and a woman, 23 was detained on suspicion of conspiring to commit a robbery. They both remain in custody, authorities confirmed.
The arrests come after an investigation into an attack at the multi-storey car park at Heathrow's Terminal 3 on Sunday. Before the incident, two women had stolen from them their suitcases after getting out of a parking garage elevator.
A three-year-old girl was one of the injured during the incident. A total of five individuals went to hospital for treatment and have since been discharged.
Officers arrested a 31-year-old man on suspicion of robbery and assault close to the scene. He has since been released under investigation while inquiries continue.
Police were alerted at approximately 8:10 in the morning GMT following reports of several people hurt by an irritating chemical believed to be an irritant spray.
The attack - an event that police said was a standalone incident and not being treated as an act of terror - resulted in train delays and the temporary shutdown of the Central Terminal Area tunnel and the Terminal 3 parking facility for a short time.