The daughter of a man who died inside a betting shop has claimed the Met Police "being too stretched" affected the outcome of the murder investigation.
Babatunde Awofeso, 53, died on 4 April after being punched at a Betfred branch in Upper Clapton Road, Hackney.
City of London Police took the case on to help the Met cope with a spike in homicides in early April 2018.
A 26-year-old suspect was later told he had "no crime to answer" and the murder case was closed in November.
Colleen Awofeso, from Devizes in Wiltshire, says she is confused by a suggestion from City of London Police that CCTV inside the Betfred shop was "corrupt" and irretrievable.
This appears to contradict comments in an email, seen by the BBC, sent by a Betfred employee who said the CCTV was working on the day Mr Awofeso died.
She said: "I'm not looking to blame anyone; all I am looking for is answers, as the facts I have been given so far don't add up.
"My family liaison officer told me my dad died because of a bad heart, but the suspect admitted in his statements that he hit my dad in the chest."
She added that a witness said the suspect had intended to hurt her father.
"Several other statements say people in the Betfred, including staff, were drinking rum and vodka to celebrate someone coming out from prison," she said.
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On the day he died, Mr Awofeso approached a man he suspected of previously stealing his bank card.
Witnesses described the argument turning aggressive and seeing the suspect follow Mr Awofeso down a corridor and out of sight.
After the incident, the suspect left Betfred and Mr Awofeso was later found unresponsive and pronounced dead at the scene.
His death came at a time during which the Met launched seven murder investigations in four days.
As a result, the force accepted a loan of murder detectives from the City of London Police.
The Met said that the forces often shared resources, although this is understood to be the first time a murder investigation has been passed between the forces.
A spokesman said: "City of London Police approached the Met to offer assistance.
"The investigation was led by Supt Lee Presland, from City of London Police, and a former Met officer."
But Ms Awofeso believes the pressure on the Met had an impact on the investigation.
She said: "The first I became aware of the case being handed over was when I met the family liaison officers - they were from the City of London Police.
"I understand the Met's resources were stretched, but what I do not get is why my dad's case was the one which got passed.
"Had the case been carried out by the Met from the start, then the outcome might have been different.
"But the way it has been dealt with makes me trust the police less and makes me think they don't care."
London's victims in 2018
Motives and circumstances behind killings varied - as did the age and gender of the victims.
Betfred said it had "fully co-operated" with the investigation, but would not comment ahead of Mr Awofeso's inquest, which is due to take place later at Poplar Coroner's Court.
City of London Police said the murder investigation was "conducted diligently and followed all of the nationally-approved procedures".
A spokesman added: "All lines of inquiries, including those relating to digital media and CCTV, were fully explored.
"The digital CCTV system within the venue was the subject of a detailed examination by forensic experts.
"They were unable to obtain images of the incident. All other evidence gathered was fully considered in consultation with the Crown Prosecution Service in making a decision on the outcome of the case.
"The City of London Police would like to take this opportunity to express our condolences to the family of Mr Awofeso for the loss they have suffered."