Seven people have been arrested as a result of parents acting as vigilantes and posing as underage children to entrap paedophiles.
The Letzgo Hunting group trick unsuspecting paedophiles into meeting up by pretending to be children. They then film their confrontations and post the videos online.
Police forces across the Midlands have made arrests as a result of information gathered by Letzgo Hunting, but warned their actions could undermine efforts to carry out police investigations.
Leicestershire Police arrested a 54-year-old man, a 24-year-old man and a 33-year-old man as a result of information passed on by the group.
Warwickshire Police have also arrested three men on suspicion of sexual grooming. All have been released on police bail pending further enquiries.
The latest person to be arrested was a 45-year-old from Sutton Coldfield. Leicestershire Police arrested him after his communications with what he thought was a 15-year-old girl.
One of the group's leaders, known only as Scumm Buster, said: "It's amazing to watch their faces drop as they realise they are not meeting who they thought they were.
"This guy from Birmingham was the biggest scumbag ever. The stuff he was saying was just vile.
"He took a lot of steps to make sure we were real. He said he'd been duped before. He asked us for pictures, phone calls. He asked us for sexual photographs as well, but anything explicit we declined.
"He reiterated quite a lot of times that he couldn't believe a girl that age was interested in him."
The group said it removes the videos it posts online once the person has been arrested and will repost once they have been tried.
However, investigators said "naming and shaming activities" can have a negative effect on child abuse victims.
A spokesman for Leicestershire Police said: "While we understand the strong feelings that motivate this kind of activity, it can seriously affect the chances of success in court, preventing victims from getting justice and increasing the chances of offenders walking free.
"It also fails to take into account that many victims of child abuse are the children or family of the offenders, thus bringing extra distress to innocent people and affecting our ability to safeguard victims.
"This is one of the reasons why you would never see any of the legitimate crime agencies doing it this way."