Detectives investigating the cause of an explosion which killed five people are appealing for witnesses.
The blast, which left three members of the same family dead, destroyed a mini supermarket and a two-storey flat on Hinckley Road, Leicester, on Sunday shortly after 7pm.
Officers want to speak to anyone in the area around the time who may have noticed suspicious behaviour, Leicestershire Police said.
The scene on Hinckley Road in Leicester (Joe Giddens/PA)
Detective Inspector Michelle Keen said: “What you saw may have seemed innocent and innocuous.
“But no matter how small the detail, no matter how insignificant it may have seemed, we need to speak to you. The information you have may be critical in this inquiry.”
Three men, all in their 30s, from East Anglia, the North West and the East Midlands, were arrested on suspicion of manslaughter on Wednesday.
They continued to be questioned on Friday morning.
The five victims are Mary Rajoobeer, 46, her two sons Shane, 18, and Sean, 17, Leah Beth Reek, 18, who was Shane’s girlfriend, and Viktorija Ljevleva, 22.
Specialist officers continued to sift through the wreckage in search of clues, with the scene expected to remain cordoned off for several days at least.
Ms Keen added: “It’s vital that we speak to anyone who may have information about any people they saw coming and going into the supermarket in Hinckley Road in the hours leading up to the explosion.
“Was there anyone acting strangely or in a suspicious manner? Did you see any vehicles parked up, or being driven in a strange manner in the area around the supermarket?
“People lost their lives in the most horrific way on Sunday. We owe it to them to understand the cause of that explosion.”
Anyone with information should call 101 quoting incident number 443 of March 1.