Police are searching parts of County Durham after a woman was found covered in blood making claims she had attacked a man.
The woman flagged down a car and later a taxi at the Jolly Drovers roundabout in Leadgate at 0200 BST on Monday.
She was said to be hysterical and splattered with blood and claimed that she had assaulted a man.
Police later arrested the woman at a house in Reynolds Close in Stanley, and she is being questioned by officers.
The 27-year-old woman told police she had been in Trades nightclub on Sunday night.
Around 20 detectives are working on the case and search and rescue teams have been drafted in to search for a possible victim.
Det Ch Insp Andy Reddick said: "Due to the woman's distressed state and the amount of blood on her we have a major concern that someone could be seriously injured and need of urgent medical treatment.
"Because of this we are conducting a thorough search of the area. Quite obviously something serious has taken place."