A man has been arrested on suspicion of attempted murder after a stabbing in Bradford left another man critically ill in hospital.
The victim, a 29-year-old Latvian man, suffered a chest wound in the attack on Infirmary Fields, a park off Lumb Lane, Manningham, on Saturday afternoon.
A West Yorkshire Police spokesman said the victim was in critical condition at Bradford Royal Infirmary.
The 35-year-old suspect, also Latvian, was arrested on Saturday night.
Police praised the "public-spirited actions" of passers-by who administered first aid to the injured man before emergency services arrived.
Det Supt Steve Payne, who is leading the investigation, urged any witnesses to contact police.
"This incident took place at a busy time of the afternoon in Bradford," he said.
"We believe a number of people may have been nearby and witnessed either the attack, or have seen someone running from the scene."