Property owner 'shocked' after police claim house fire was arson

The owner of an Adelaide property destroyed in what police say was a deliberate arson attack says he is "shocked" and unaware why he might have been targeted.

The fire took hold of the Grand Junction Road house and shopfront at about 7pm last night.

"We heard an almight bang, a huge blast," witness Sammy Zirilli said.

"Twenty to 30 seconds after the blast it was well alide, so there was no fighting that fire."

Firefighters were able to prevent the blaze spready but the building - which had tenants in it until just weeks ago - was gutted.

Owner Suresh Kumar was left devastated.

"I am feeling very bad, so I can't explain how I am feeling," he said.

Police say it is possible drivers travelling along Grand Junction Road with a dash cam may have captured the offenders and are urging anybody in the area with vision to come forward.

Anybody with information is urged to contact Crime Stoppers on 1800 333 000.