An additional two individuals are now in custody related to a robbery at London's Heathrow Airport in which 21 people sustained injuries by a substance believed to be pepper spray, according to law enforcement.
A 24-year-old man, was arrested in Lambeth on suspicion of robbery and assault and a woman, 23 was arrested on suspicion of conspiring to commit a robbery. Both individuals are still being held, the force said.
The arrests come after a probe into an attack at the multi-storey car park at Heathrow's Terminal 3 on Sunday. Before the attack, two women had stolen from them their luggage upon exiting a car park lift.
A three-year-old girl was one of the those hurt during the incident. Five people were taken to the hospital for medical care and were later discharged.
Officers detained a 31-year-old man for suspected robbery and assault close to the location. He was subsequently released under investigation as the investigation proceeds.
Police were alerted at about 08:10 GMT after reports came in regarding a number of people injured by a noxious substance thought to be an irritant spray.
The attack - an event that police said was a standalone incident and not considered an act of terror - caused train delays and the temporary shutdown of the Central Terminal Area tunnel and the Terminal 3 car park for a short time.
