A true crime writer convinced he knows who raped and murdered an 11-year-old girl more than 70 years ago has lodged a formal complaint with police over their handling of the investigation.

Sheila Martin was strangled in Sun Hill Wood, Fawkham Green, in July 1946, 10 days after 12-year-old Muriel Drinkwater was raped and shot in woods near her home, more than 200 miles away in Swansea.

It was not until 2009 that Welsh detectives linked the killings and asked Kent Police to send them the original case file.

Welsh author Neil Milkins has been investigating Muriel’s murder for the past decade and is certain he knows who killed both girls.

The 65-year-old is convinced Harold Jones – a convicted child killer from Monmouthshire who died in 1971 – was guilty.

Jones had been jailed for 20 years in 1921 after admitting murdering 11-year-old Florence Little and eight-year-old Freda Burnell.

Mr Milkins has also previously accused Jones of being behind the unsolved ‘Hammersmith nude murders’ of six prostitutes in the 1960s.

Despite contacting South Wales Police on numerous occasions regarding the investigation Mr Milkins says he has been treated with “disdain and disrespect” by former and serving officers.

He says the force will not discuss with him if Jones was or remains a suspect and have now shelved the investigation and the Sheila Martin case file once again.

He said: “I think they’re embarrassed because they were convinced 13-year-old Hubert Hoyles, who was the last person to see Muriel alive, was her killer.

“They focused only on him and he had to live under that shadow until DNA eventually cleared him of any involvement.

"They missed opportunities to question Jones and now they’re embarrassed that they got it badly wrong.

“I’ve made this complaint not just because I am fed up with how I’ve been treated but because I think by treating me in this way South Wales Police have jeopardised their investigation into these murders.”

Kent Police spokesman Nicola Forman said: "We sent the original case file to South Wales Police who were looking at the Muriel Drinkwater case to see if there were any possible links with our case (Sheila Martin).

"However, we are not reinvestigating the Sheila Martin murder from a Kent Police perspective."