The families of four gay men poisoned by Stephen Port will sue Scotland Yard because a 'five-year-old child' would have deduced they were murdered before their detectives did.
The Met repeatedly said the similar deaths in Barking over 15 months were all not suspicious before serial killer Port was arrested last year.
Jack Taylor, 25, Anthony Walgate, 23, Gabriel Kovari, 22, and Daniel Whitworth, 21, were all murdered by Port but initially they were considered self-administered overdoses and not linked.
All were given lethal amounts of so-called 'chemsex' drug GHB - abused while unconscious - and dumped in the street or the local graveyard.
Port even went to prison for lying about about Mr Walgate's death but officers still failed to work out he was a murderer and he was released before killing again.
Mr Walgate's mother, Sarah Sak, said today: 'A five-year-old child could have put the clues together'.
She said: 'It was homophobia. He had planted GMB on them. The police thought "young gay lad. Oh he's had chemsex. Done".'
'They were like that from the beginning, they just refused to investigate anything, didn't matter what you said to them they kept telling us there was nothing to investigate.'
Well done Plod!