Detectives were questioning two men today in connection with a suspected arson attack at a bail hostel which killed four residents.
West Midlands Police detained the suspects following the blaze which swept two rooms at Fairlawns Hotel in Birmingham.
Three men and a woman were in two ground floor bedrooms at the rear of the property which were engulfed by flames yesterday evening.
Police and fire forensic experts remained at the three-storey building today trying to establish the cause of the tragedy.
The property lies along Hagley Road in Edgbaston, one of the city's busiest commuter routes, which was sealed off in both directions as police officers stood guard outside the premises.
The Fairlawns is one of many hotels and hostels along the road providing accommodation for defendants involved in court proceedings as well as homeless.
It is understood there is room for around 50 residents, though only around 20 were in the building when the alarm was raised shortly before 9.10pm.
At the scene today, Detective Chief Inspector Russell Smith described the fire as "very severe".