A flammable substance was poured under a window before being set alight in an arson attack in Wellingborough.
The incident happened on Sunday, August 5, between 1.15am and 1.50am, at a property in Windmill Close.
The offender/s entered the garden, poured a flammable substance under a downstairs window and ignited the fluid, causing a fire.
The fire then spread across the house.
A 39-year-old woman has been arrested in connection with the incident and released under investigation pending further enquiries.
Officers are now appealing for anyone who witnessed the incident or anyone who may have any information regarding it to call police on 101 or Crimestoppers anonymously on 0800 555111.