A man remains in critical condition after being assaulted at the Barking Asda on Saturday night.
At 11.59pm on June 18, police were called to reports of an assault inside a supermarket in Short Blue Place.
A member of the public assaulted two members of staff after reportedly gaining entry into the shop while it was closed.
Officers attended and found a man, believed to be aged in his 60s, suffering from a head injury.
He was taken to hospital by London Ambulance Service crews where he remains in a critical condition.
A second man who was also assaulted did not suffer serious injuries.
Police arrested a 27-year-old man on suspicion of GBH at the scene.
He remains in custody.
Enquiries continue.
Asda has been contacted for comment.
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