A woman in her mid-thirties was found in Lower Cross Street, Spring Boroughs, having been assaulted.
She was discovered at about 4pm on Saturday, May 14.
Northamptonshire Police would like to speak to anyone who may have witnessed the attack or who may have any information about it.
Witnesses or anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 111 55. Alternatively, you can use the online form at www.crimestoppers-uk.org