Police have warned self-styled paedophile hunters against confronting suspected child abusers after five of them were arrested on suspicion of wrongful imprisonment and assault.
The three men and two women were detained in Leeds on Monday. They are also being investigated for public order offences.
In a statement, West Yorkshire Police said concerns about "illegal internet activity of potential child abusers" should be always reported.
It said: “We are also concerned about the activities of online child abuse activist groups and their exposure activity in confronting persons they have identified.
"We urge members of such exposure groups not to carry out this activity and instead to report suspected offences."
Increasing numbers of so-called paedophile hunters – many with ominous names such as Dark Justice – have been operating across the UK over the last decade.
They say they do so in a bid to keep children safe online, and claim their activities are often supported by rank-and-file officers.
But senior officers at police forces across the country have repeatedly expressed concern about their activities.
In several instances groups have live-streamed footage of them confronting the wrong person. In several more, such citizen arrests have turned violent.
At least eight men confronted by the groups have gone on to take their own lives, the BBC found last month.
West Yorkshire Police said the five arrests were related to offences alleged to have occurred in Wakefield on 11 August last year and in Leeds on 13 January. All five suspects, who have not been named, were released on bail.
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