Four children aged 12 and under have been arrested on suspicion of arson after a home was set ablaze.
Officers from Beds Fire and Rescue were able to extinguish the fire on Sherd Close, Luton, at 4.15pm on Sunday June 15, but not before extensive damage was caused to the wall of the property.
Two girls, aged 12, and two boys, aged 10, were arrested on suspicion of committing arson by officers close to the scene.
All four have been released on police bail while fire and police investigators continue their inquiries.
Police continue to look for witnesses to the incident, as well as to another fire which saw more than 30 firefighters sent to Leagrave High Street on Wednesday,
The fire at Westlea, a former residential care home, was first reported at 10.15pm after 17 separate 999 calls were made.
Two fire crews from Dunstable arrived at the scene within minutes to find that a quarter of the roof of the unoccupied two-storey building was already well alight.
Two further fire appliances from Luton Fire Station were sent to assist.
The aerial platform from Luton and the incident command unit from Leighton Buzzard were also sent to the scene, as well as a water carrier from Toddington, to supply additional water for the fire crews tackling the blaze.
Firefighters in breathing apparatus used three jets to fight the fire, using a monitor from the aerial platform to assist from above the building.
The fire was declared under control at 2.12am on Thursday morning.
Half of the roof space was destroyed by the fire and the whole building was affected by heat, smoke and water damage.
An investigation into the cause of the fire is underway.
In October 2012 the two acre site was placed on the market by the council for £1.5m.
Both fires are not thought to be linked, but Beds Police is seeking for witnesses to both incidents,
Detective Constable Jabbar Khan said: “Although there have been arrests in connection with (the June 15) incident I would like to urge anyone who saw or heard anything suspicious in the Sherd Close or Leagrave High Street area to contact the police.
“Luckily on both occasions no one was hurt but these fires could have caused structural damage to the buildings and put members of the public, neighbouring properties and members of the emergency services at great risk.”