The stepmother of one of serial killer Stephen Port's victims has said she is "disgusted" by the police's failure to conduct tests on a fake suicide note.

Mandy Pearson said her family were assured that the handwriting on the note found with the body of Daniel Whitworth would be properly checked.

Detectives treated the 21-year-old's death as non-suspicious because of the note, which had been written by Port.

Port, 41, was given a whole life prison term for the murders of four young men.

Mr Whitworth, from Gravesend, Kent, was found dead in an east London churchyard near Port's home on 20 September 2014, three weeks after the body of another Port victim - 22-year-old Slovakian Gabriel Kovari - had been found in the same spot.

The note in Mr Whitworth's hand said he had accidentally killed Mr Kovari and was taking his own life as a result.

Port, from London, had murdered both men and would go on to kill again a year later.

Image copyright Facebook Image caption Daniel Whitworth, 21, was found dead in a Barking churchyard in September 2014

On Thursday the BBC revealed how a detective told Mr Whitworth's inquest that police officers had checked the note against one of Mr Whitworth's diaries, but that a handwriting expert had not been consulted.

When it was eventually checked, an expert concluded that the author of the note was not Mr Whitworth but the handwriting was a match for Port's.

'We trusted them'

Speaking for the first time, Ms Pearson says she remembers the initial contact from detectives.

"We were told that it looked like he'd taken his own life as he'd been found with a letter - and we were very, very keen to see it," she told the BBC.

When the family saw the note they were not convinced.

"We said we weren't sure. Especially when we did finally see the whole thing."

The family told police that "there was nothing personal about it. There were no names mentioned".

"We said then there was nothing there that would link it to Daniel. Nothing at all. His circumstances were looking good, things were bright, he had a good future ahead of him."

The family were not even that familiar with Mr Whitworth's writing, she recalls.

"In this age when you're using email, texts - it's very seldom you see handwriting unless it's in a card," she said.

But when they looked at some cards sent by Mr Whitworth, she said, the writing was not a match.

Image copyright Met Police Image caption Port, 41, from London, was given a whole life prison term on Friday for the murders of four young men

Ms Pearson says the family were assured by the police that the handwriting would be properly checked.

"They said they were going to do that anyway. They took samples, they took the cards."

Asked how she feels knowing that the tests were not done, she said: "Disgusted. We feel disgusted."

"We put our confidence in them. We trusted them."

But she also praised the Met detectives who later conducted the successful investigation.

The police watchdog is investigating how the serial killer case was handled.

The Independent Police Complaints Commission is examining the initial police response to the deaths of the four men in London.

A total of 17 Metropolitan Police officers are under formal investigation.