An additional two individuals are now in custody in connection with a theft at Heathrow Airport where 21 people sustained injuries by a substance believed to be pepper spray, according to police.
A 24-year-old man, was arrested in the Lambeth area for suspected theft and assault and a 23-year-old woman was detained on suspicion of conspiring to commit a robbery. Both individuals are still being held, the force said.
The arrests follow a probe into an attack at the multi-level parking garage at Terminal 3 on Sunday. Before the attack, two women were robbed of their luggage upon exiting a car park lift.
A three-year-old girl was among the injured in the event. Five people were taken to the hospital for medical care and have since been discharged.
Officers arrested a man in his thirties for suspected robbery and assault close to the scene. He was subsequently released under investigation while inquiries continue.
Police were called at approximately 8:10 in the morning GMT after reports came in regarding several people hurt by an irritating chemical believed to be pepper spray.
The attack - which police said was a standalone incident and not being treated as an act of terror - caused train delays and the temporary shutdown of the main airport tunnel and the Terminal 3 parking facility briefly.
