A man suffered a puncture wound to his chest after an attack in Halifax on Sunday night.
The 18-year-old man was found by a member of the public on Dudwell Lane at 9.39pm.
The man was taken to Leeds General Infirmary with the injury, which is believed to have been caused by a small rounded instrument.
Police believe it was a targeted incident.
The man suffered minor injuries.
Police enquiries are ongoing.