Police say up to 10 men entered the Glen & Co Cash and Carry in Barking yesterday morning.
Shammi Atwal and his wife - who are co-owners of the business - tried to stop them, causing the gang to flee.
Detective Chief Inspector Neale Baldock said: "This was a man trying to stop thieves robbing his business. He acted bravely in defence of his wife and managed to chase the robbers from his premises only for him to be pushed in front of a moving lorry.
"People in the community know who committed this appalling and cowardly crime and I would urge them to contact my officers."
More top news
The family of Oliver Dearlove urged people to "think again" before using their fists, as the man who killed him began a six-year jail term.
London Fire Brigade took Southwark Council to court on four charges in relation to safety breaches at Lakanal House in Camberwell.
Oliver Dearlove died 24 hours after receiving the fatal blow outside Morden's wine bar in Blackheath last summer.