Police in Cardiff are investigating a third sex attack in just five days.
Detectives were called to Gorsedd Gardens in the Welsh capital's civic centre at around 4.30am today after a serious assault on a woman.
The crime scene is just a few yards from where a similar attack took place on Sunday - and little over half a mile from another which took place on Tuesday morning.
All three victims are women.
South Wales Police Superintendent Andy Valentine said while a man had been arrested, inquiries were still at an early stage.
He said: "While there are similarities in terms of the locations, times and nature of the offences, it is too early to say whether the same man is responsible.
"We are working extremely hard to identify who is responsible and the victims are being supported by specially trained officers."
Earlier this week, police launched an appeal for information after a 20-year-old woman was sexually assaulted near Cardiff University's main building at 3am on Sunday.
On Tuesday, officers again asked the public for help after a woman was attacked in Cathays Terrace during the early hours of the morning.
Detectives later urged people walking around at night to do so in pairs or groups.