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, as stated by law enforcement.
A man, 24, was arrested in the Lambeth area for suspected robbery and assault and a woman, 23 was detained on suspicion of conspiring to commit a robbery. Both individuals are still being held, authorities confirmed.
The arrests follow a probe into an attack at the multi-level parking garage at Heathrow's Terminal 3 on Sunday. Prior to the attack, a pair of female travelers had stolen from them their suitcases after getting out of a car park lift.
A three-year-old girl was among the those hurt in the event. Five people went to hospital for treatment and were later discharged.
Officers detained a 31-year-old man for suspected robbery and assault close to the scene. He was subsequently released pending further inquiries as the investigation proceeds.
Authorities were alerted at approximately 08:10 GMT following reports of a number of individuals hurt by an irritating chemical thought to be pepper spray.
The assault - an event that police said was a standalone incident and not considered terrorism - caused train delays and the partial closure of the Central Terminal Area tunnel and the T3 parking facility for a short time.
