Firefighters remain at the scene at William House in Marsh Lane, Walsall, this morning, where flames erupted from windows and onto the roof of the building last night.
It comes after 45 firefighters were called to an arson attack at former leatherworks Greatrex House in June last year, which was on the same street.
Nearby homes were evacuated and roads were closed as smoke poured over the area during the blaze on Thursday.
West Midlands Fire Service's investigators have now said they believe the fire was started deliberately and are working with a Walsall Council structural engineer this morning who is assessing the safety of the building.
West Midlands Fire Service tweeted saying: "Our investigators believe last night’s fire in Walsall was started deliberately.
"We have one crew still at the scene and will be working with a Walsall Council structural engineer who will be assessing the safety of the building this morning."
The fire service was first alerted to the blaze at 6.24pm yesterday with multiple 999 calls received.
Jamie Arrowsmith, spokesman for West Midlands Ambulance Service, said: "We were called to reports of a building fire on Marsh Lane at 6.43pm, one ambulance, two paramedic officers and our Hazardous Area Response Team were sent to the scene. However, there were no patients found from the property, and after working with emergency service partners to ensure the scene was safe, we were stood down."
Residents in the area were asked to keep their windows closed.
Evacuated residents were returned to their flats once the fire had been extinguished at around 9.40pm.
A worker at nearby TC Performance, in Navigation Street, said they had gone home last night when the fire started but when they learned of the blaze they were "not surprised" as it happened last year.
The man, who did not wish to be named, said: "The same thing happened in the building opposite last year, they knocked it down.
"It wasn't a shock, it just happens."
A spokesman for West Midlands Fire Service said: "We sent seven fire engines and one hydraulic aerial platform.
"A neighbouring property was evacuated, that was done with support of West Midlands Police as a precaution in case the fire spread but fortunately our crews worked really hard to ensure that didn't happen.
"That building had been evacuated fully by 6.45pm, police also assisted us with road closures.
"We used water from a nearby canal, the fire was confirmed to be out by 4.50pm.
"The council is sending a structural engineer to assess the building.
"The building is four storeys and measured 40 by 40 metres."
Anyone with information is urged to contact fire or police services.