This is the dramatic moment a group of bodybuilders wrestled a suspected bogus caller to the ground who allegedly tried to steal from them in their own gym.
CCTV captured the moment the musclemen sprang into action after learning that the man had allegedly tried to swindle money from them by falsely claiming to be collecting funds for sick children.
The drama unfolded at the Muscle Madness Bodybuilding Gym in Sheffield when a 'scruffy looking man' walked in and claimed to be collecting money on behalf of Bluebell Wood Children's Hospice.
But the suspicious gym owner David Grubb put calls into police and discovered he was in fact a suspected bogus caller who had been operating in the area.
A group of bodybuilders then wrestled him to the ground and made a citizens arrest. CCTV footage captured the dramatic moment they held him down until a team of police officers swooped to the scene to take him away.
Mr Grubb, a father-of-five, said: "I knew something wasn't right about him - and when police confirmed it I knew we had to take action.
"When he came in I put his arm behind his back and a few of the other lads held him down until police arrived.
"It was quite shocking, the adrenaline was pumping, but he chose the wrong gym. I'm not having people stealing from us, especially when they claim to be collecting for a charity - it's a disgrace."
The 51-year-old was at the reception with a colleague when a man believed to be aged in his mid-30s and dressed in a hospice t-shirt walked in carrying a bucket at at about 10.30am on Monday.
The gym owner said he 'looked scruffy' and couldn't provide proper proof of identification so he invited him to return at 5pm that evening when more gym members would be available to donate.
Mr Grubb said he called police who told him the man was a suspected bogus caller, meanwhile staff at the hospice also confirmed on the phone that none of their official fundraisers were operating in the area.
Mr Grubb, who lives with wife Carolyn in Manvers, Rotherham, added: "I couldn't believe it when he walked back in. I locked the doors behind him and a couple of the lads came over and we restrained him.
"He was shouting for us to get off him. I called police and made sure we weren't putting too much pressure on him. Three police cars and about eight officers got here shortly after and took him away."
Two other gym users, door supervisors Francois De La-Gron, aged 23, of Westfield, and Isacc Glave, aged 20, of Sheffield, assisted in the citizens arrest.
Francois said: "I couldn't just stand back, I needed to do something." Isacc added: "I am glad we restrained him after finding out what he is alleged to have done."
Pictures of the citizens arrest at the Effingham Road gym in Attercliffe have since gone viral on Facebook. They have been seen by more than 85, 000 people and 'liked' by around 1000 others.
The gym has since launched a fundraising page for Sheffield-based Bluebell Wood Children's Hospice - which cares for children with a shortened life expectancy in South Yorkshire - and it has so far raised more than £200 towards a £1000 target.
Mr Grubb said: "The response we have had on Facebook has been amazing. We just wanted to turn a negative into a positive. I hope the man has learned his lesson."
South Yorkshire Police confirmed a man had been arrested over the incident.
To donate to the fundraising page visit https://www.justgiving.com/fundraising/Musclemadnessgymsheffield?utm_id=26