A care worker suffered a bleed on the brain after being assaulted on her way to work in Marsh Road.
The woman, 25, was on her way to the nursing home when she was approached from behind and hit over the head.
She managed to get to work where her colleagues called the ambulance service and police.
The victim is now at home recovering from her ordeal and Pc Olyver Tomlinson is looking for witnesses.
He said: “There appears to be no motive as to why this assault took place and at this time we are still seeking information that can help us identify the offender. This incident took place opposite the British Legion Pub and on a busy street so anyone who was passing in a vehicle or someone walking in the area may have noticed someone behaving suspiciously that night and I would urge these people to talk with officers.”
Anyone with information relating to this crime can contact PC Tomlinson at Luton Police Station, in confidence, on 01582 394158, or Bedfordshire Police on 101, or text information to 07786 200011.
Alternatively contact the independent crime fighting charity Crimestoppers, anonymously, on 0800 555 111.