A sixth man has been arrested in connection with the explosion in Leicester that killed five people.
Detectives investigating the blast in Hinckley Road on February 25 said they have arrested a man in his 40s from East Anglia on suspicion of manslaughter.
Three men are due in court on Monday charged with manslaughter and arson with intent to endanger life.
Two other men from East Anglia were arrested on Friday in connection with the incident but have since been released under investigation.
In a statement on Sunday evening, the force said: “Detectives investigating the explosion in Hinckley Road, which happened a week ago and resulted in the death of five people, have made a further arrest.
“A man in his 40s, from East Anglia, has been arrested on suspicion of manslaughter. He is currently in police custody where he will be questioned by detectives.
“Two other men, both in their 30s and from East Anglia, who were arrested on Friday have since been released under investigation.”
Aram Kurd, 33, Hawkar Hassan, 32 and Arkan Ali, 37, were arrested on Wednesday and now each face five counts of manslaughter and arson with intent to endanger life.
Three members of the same family died when the Polish supermarket and a two-storey flat above it on Hinkley Road were destroyed around 7pm last Sunday.
Several other people were also injured, one of whom suffered critical injuries.
Mary Ragoobar, 46, and sons Shane, 18, and Sean, 17, lived in the flat above the shop.
Sean and Shane, along with Shane’s girlfriend Leah Beth Reek, 18, and Viktorija Ijevleva, 22, who was working in the shop at the time, have been confirmed as among the dead.
The fifth body is still to be formally identified but is believed to be Mary, officers said.