Two more people are now in custody related to a robbery at Heathrow Airport where 21 people sustained injuries by what is thought to be an irritant spray, according to law enforcement.
A man, 24, was taken into custody in the Lambeth area for suspected robbery and assault and a woman, 23 was detained for suspected conspiring to commit a robbery. Both individuals remain in custody, the force said.
The arrests follow a probe into an assault at the multi-storey car park at Heathrow's Terminal 3 on Sunday. Prior to the incident, two women were robbed of their suitcases after getting out of a car park lift.
A toddler aged three was among the those hurt during the incident. Five people were taken to the hospital for medical care and have since been released.
Police arrested a man in his thirties on suspicion of theft and assault close to the location. He was subsequently released pending further inquiries while inquiries continue.
Police were alerted at about 08:10 GMT following reports of several individuals hurt by an irritating chemical thought to be pepper spray.
The attack - which authorities stated was a standalone incident and not being treated as an act of terror - caused train delays and the partial closure of the main airport tunnel and the T3 parking facility briefly.
