Tens of thousands of pounds worth of damage caused at Oswestry branch by fire, which firefighters believe was started deliberately.
Two fire engines were called to a Homebase store in Oswestry, Shropshire last Wednesday to battle the blaze, which destroyed a number of industrial skips and a large storeroom at the back of the premises.
The fire triggered the store's sprinkler system in the main building, causing further damage to stock. No one was injured in the blaze.
Police are treating the incident as suspicious and are keen to hear from anyone who may have been in the Salop Road area near the Homebase store between midnight and 12.10am in the early hours of Thursday morning, when it is believe the fire was started.
Detective constable Dave Harris of Oswestry CID said: "I am particularly keen to speak to the driver of what appears to be a private coach or bus, which was seen travelling along Salop Road just after midnight.
"There was also a small hatchback travelling in the opposite direction and which the driver of the coach will have seen."
He added: "We are also keen to hear from anyone who might have been out walking in Salop Road at the time, perhaps on their way home after a night out."
Forensic officers have examined the scene and CCTV footage is being analysed.
Anyone with information is asked to contact West Mercia Police on 0300 333 3000 or anonymously via Crimsetoppers on 0800 555111.
In other news, a Wyevale garden centre became fell victim to arsonists who lit a series of fires across east Brighton in the early hours of Monday morning.
A pile of wooden pallets and a car were set alight in the centre's car park in Warren Road. Firefighters were called to the scene at 3am and had to spend nearly three hours putting out the blazes.
Anyone with information about any of the fires should contact Sussex Police on 0845 607 0999.