Humberside Police said National Crime Agency experts were helping to establish "if what has been respectfully recovered are in fact human ashes".

"I can confirm that whilst formal identification procedures are ongoing, we do believe we have contacted all families of the 35 deceased," said Assistant Chief Constable Thom McLoughlin.

More than 1,500 calls have now been received to a phoneline for people who used Legacy Independent Funeral Directors.

Two people - a man aged 46 and a woman aged 23 - were arrested on suspicion of prevention of a lawful and decent burial, fraud by false representation and fraud by abuse of position.

They have been released on bail while the investigation continues.

Families have spoken about their anguish at not knowing how their loved ones were treated and whether they were given the right ashes.

A woman whose husband's cremation was organised by the company told Sky News she feels "numb" amid the wait for answers.

"I can't cry, I can't get angry. I just genuinely feel numb. I just don't know what to think. I just really don't know," said Louisa Millington.

Billie-Jo Suffill, 33, told the Daily Mirror she felt "physically sick" because she never received her father's ashes.

"I bet my dad was not even in the coffin - it was an empty coffin," she said.

"I was kissing an empty coffin. When I think about it, it is disgusting. It's like something out of a horror movie."

The remains were recovered last Friday and Saturday at a Legacy office on Hessle Road in Hull and moved to a mortuary for identification.

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Police said their operation at Hessle Road ended on Thursday but that a "scene guard" remained in place.

Three branches were raided in all, two in Hull and one in Beverley, over concerns about "storage and management processes relating to care of the deceased".

The local council and coroner are also involved - and police have called it an "intricate" and "truly horrific incident".

Legacy is a family-run business established in 2010, according to its website. It has yet to comment publicly.