A man arrested in connection with the stabbing of a woman in a Whiston park has been detained under the Mental Health Act.
The 18-year-old was arrested on Saturday after police were called to Stadt Moers Park in Whiston.
Officers arrived to find a 55-year-old woman had received several stab wounds.
She was taken to hospital where her condition is described as stable.
The suspect, who is from Huyton, was arrested a short time later.
He has been questioned by detectives but has now been sectioned under the Mental Health Act.
Officers closed off parts of Stadt Moers Park while forensics examinations took place.
Nearby CCTV will also be examined by officers as part of their investigation.
Det Chief Insp Chris Sephton said: “This investigation is at a very early stage and while we don’t know the motive for the incident, this must have been a horrific ordeal for this woman.
“While we have one man in custody, I’d also like to reassure local residents that there will be a highly visible police presence in the area.
“I would also like to take this opportunity to urge anyone who may have witnessed this incident, or who has any information about it, to contact Knowsley CID via 101 or Crimestoppers anonymously on 0800 555 111.