A teenager has been arrested on suspicion of grievous bodily harm and robbery after a pair on a moped carried out five acid attacks in London.
Metropolitan Police said they were treating the attacks within 90 minutes on Thursday night as linked.
The assaults involved the pair attacking other moped riders and allegedly stealing two bikes.
At the start of the rampage, a 32-year-old moped rider was approached as he drove towards the Hackney Road junction with Queensbridge Road.
The two male suspects tossed the substance in his face before one jumped on his moped and rode away.
Police said the man went to an east London hospital and they are waiting for an update on his injuries.
Twenty minutes later, at around 10.50pm, another victim was sprayed with liquid on the Upper Street junction with Highbury Corner, Islington.
The victim was taken to a hospital in north London.
At 11.05pm, the two attackers swooped on a third man, in Shoreditch High Street, hurling acid in his face.
His injuries are not life-threatening, police said.
Within 15 minutes, they appeared to have struck again, throwing the corrosive liquid at a man on Cazenove Road and causing “life-changing” facial injuries.
The final assault was reported at 11.37pm, when another man was confronted as he sat on his moped in traffic on Chatsworth Road.
He was also sprayed in the face, the moped stolen and both attackers fled.
Police said the male teenage suspect remains in custody at an east London police station.
The force said in a statement: “Inquiries are ongoing and officers from Hackney CID are investigating.
“Any witnesses, anyone with information or in possession of footage of these incidents should contact police on 101 or tweet @MetCC. To remain anonymous you can call Crimestoppers on 0800 555 111.”
The attacks come days after a man appeared in court charged with throwing acid at a 21-year-old woman and her cousin.
Resham Khan, 21, and Jameel Muhktar, 37, were left with life-changing injuries after the attack in Beckton, east London, on 21 June.
There was another acid attack in east London on Easter Monday, leaving two people at a nightclub partially blinded and others injured.
A petition to restrict the sale of acid and bring in a licence system currently has more than 360,000 names.