An investigation has begun into Gentoo van blaze which left two other vehicles damaged.
Firefighters from Farringdon Community Fire Station were called to the Havelock Civic Buildings, off Hylton Road, at the rear of Ford Post Office, shortly before 9pm yesterday.
Two crews arrived at the scene to find the Gentoo base was still locked up and used a ladder to get into the car park.
A firefighter wearing breathing apparatus used a hose reel to put out the blaze.
It is believed the fire was started maliciously when a van was broken into and then spread to neighbouring vans.
Today, Northumbria Police has started to carry out an investigation into the incident.
A spokeswoman for the force said: "At about 9.10pm, yesterday, police received a report of a vehicle on fire in Sunderland.
"Emergency services attended and discovered a van on fire at Havelock Civic Building on Hylton Road.
"The fire was extinguished and inquiries into the circumstances surrounding the fire are ongoing."
Gentoo has said it is aware of the incident and would support the emergency services in its investigation.
Anyone with information is asked to call 101 or Crimestoppers anonymously via 0800 555 111 or its website.