The families of Grindr serial killer Stephen Port's victims have renewed their appeal for information over what they have described as 'police failings'.

Last year, Port, 41, was handed a whole life sentence after a jury found he had surreptitiously given the four men fatal doses of date rape drug GHB before dumping their bodies near his flat in Barking, east London, over 15 months.

The families of Anthony Walgate, 23, Gabriel Kovari from Lewisham, 22, Daniel Whitworth from Gravesend, 21, and Jack Taylor, 25, have jointly instructed specialist lawyers as the Independent Police Complaints Commission continues its probe into the handling of the case.

They are renewing their appeal ahead of a BBC3 documentary to be aired online on Thursday.

Mandy Pearson, step-mother of Daniel Whitworth, says: “We continue to seek answers and accountability from the police about how, for a whole year, they let us believe that Daniel had committed suicide, in which time Port had gone on to kill again.

“We all hope that the documentary will be a positive experience, resulting in further potential witnesses coming forward.”

Jack Taylor’s sisters, Donna and Jen Taylor say: “Our family are grateful to the BBC for commissioning this documentary.

“It’s important that the Metropolitan Police Service understand that we will continue to highlight their failings until we get answers about their conduct and justice is done.”

Sarah Sak, Anthony Walgate’s mother says: “It was harrowing to make this documentary because we had to relive the way we were treated by the police and the loss of our loved one all over again.

“However, we agreed with Daniel and Jack’s families that their stories must not be brushed under the carpet.”

Solicitors for the families have also renewed their appeal for anyone who had contact with Port to come forward and have reassured potential witnesses that they do not have to speak to the police.

Neil Hudgell of Hudgell Solicitors said: “We’re currently gathering as much information as possible and would urge anyone who thinks they may have some relevant information, no matter how small, to contact us.

“It is crucial that we are able to build as full a picture as possible around Port’s activities, identifying any failings in the process and ultimately ensuring that lessons are learnt that will prevent the future suffering of innocent victims.

“There may be individuals out there who had contact with Port, either online or in person, or some may have been told information by another party which may be useful.

“We are fully aware of the trauma caused by Port to many individuals and we would like to reassure anyone with information that they will be treated sensitively and with respect.

“If a witness wishes to speak to the police, we will pass their details on. However, I am sure you can understand that given the circumstances some witnesses do not want to speak to the police and we will respect their wishes.”

The legal team can be contacted directly on portenquiry@hudgellsolicitors.co.uk