Police in Manchester are hunting a sex attacker who may have attacked two women in the space of an hour.
A 20-year-old woman was raped in an alleyway between Manchester Town Hall and the library shortly before 0300 GMT.
Police said CCTV footage showed a man acting suspiciously in the area about 45 minutes before the attack.
The footage also showed the man attacking or attempting to attack another woman.
Officers have appealed for the woman to contact them as she may have vital information.
The man is described as white, aged between 20 and 30, with short hair and wearing a light top.
Det Insp Mark Hudson, of Greater Manchester Police, said: "It is clear the woman who is speaking to us was subjected to a nasty attack.
"She is being supported by specially trained police officers and we are doing all we can to catch the offender.
"I'd really like to hear from that other woman.
"I'd also like to appeal to anybody who was out in the early hours who has seen anyone acting suspiciously in the area."
Anyone with information has been asked to contact Greater Manchester Police or Crimestoppers.