An armed 17-year-old boy was arrested by police after a teenager was knocked unconscious near a Plymouth park.
The victim needed hospital treatment following the assault in the area of West Park, Plymouth on March 6.
The 17-year-old male was arrested on suspicion of assault occasioning actual bodily harm, possession of an offensive weapon and resisting arrest.
He has since been released under investigation pending further enquiries.
Devon and Cornwall Police are appealing to anyone who witnessed the incident or who was in the area at the time, to get in touch by emailing firstname.lastname@example.org or call 101 and quoting crime reference CR/017567/21.