Vigilante groups today defended their work exposing paedophiles after a top Norfolk police officer warned they were putting child abuse investigations at risk.
Temporary Deputy Chief Constable Paul Sanford told the volunteers to leave the catching of paedophiles to the professionals.
The groups gather evidence by posing as children in online chat rooms and often arrange a meeting with men accused of grooming the child.
Last year three people were charged in Norfolk and five in Suffolk in cases linked to paedophile hunter groups.
This year 16 crimes have been reported to the two police forces which reference the groups.
One group, which caught a man in Great Yarmouth in 2017, said police could not deal with the "epidemic" of online grooming.
A spokesman for Net Justice said: "Unfortunately the professionals are so under-resourced that they simply cannot cope.
"On the occasions we have handed over evidence straight to the police we have waited months and months before anything is done. We just want to help."
Izzy Hunter, from group Innocent Voices, also said police did not have enough resources.
"It is really hard for police but we want the result and they don't have the time to investigate," she said.
"We have built a really good reputation with some forces. We put in a lot of work, get all the evidence together and hand it to police."
But DCC Sanford said the paedophile hunters were a "real risk" to ongoing investigations.
"They do it in absolutely the wrong way," he said.
"There is no consistency in the way the evidence is brought to us.
"My concern is they have no training in child safeguarding. They run the risk of undermining ongoing investigations.
"The groups will say, 'we are doing this because the police are not acting'.
"However our message is leave the job to the professionals. We will always investigate reports."
He added evidence was often passed to them by a group when the suspect was already aware they were being investigated.
Last week one group had to apologise after two innocent men were arrested when vigilantes live streamed a confrontation with them on Facebook.
Caught by paedophile hunters
-April 2019: David Woolston, from Great Yarmouth, jailed for three months suspended for 18 months after being caught by three sets of paedophile hunters using fake profiles. He was confronted in a car park in Caister.
-July 2018: Kevin Ward, of no fixed abode, jailed for 18 months. He agreed to meet a 14-year-old girl at Great Yarmouth library, but the "girl" was a decoy with group Net Justice
-June 2018: Liam Staff jailed for 30 months. He was chatting to a girl he thought was 13 on WhatsApp but it was a woman from a hunter group.
They confronted the 26-year old at his home on Elizabeth Fry Road.
-June 2018: Joshua King, 26, of Naseby Way in Norwich, jailed for 12 months suspended for two years for sending explicit messages online.
He was talking to a woman posing as a child and was confronted by a group called Wolf Pack Hunters UK.
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