A woman was sexually assaulted while walking through Grove Park in the early hours of Sunday morning.
The shocking attack happened as the woman walked near the bandstand at around 2am.
Detective Constable Joanne Merry said: “This was an unprovoked attack and we’re urging the public to help us identify the man responsible.
“He is described as mixed race and wearing a dark hooded top, dark grey tracksuit bottoms, with a grey scarf around his neck and black gloves.”
Anyone with information can contact the Serious Crime Investigation Team at Luton police station on 101. Alternatively text information to 07786 200 011, or call Crimestoppers, anonymously, on 0800 555 111.