Two people were arrested for public order offences in Aberbargoed last night, September 1, after it was wrongly believed a house on Commin Road contained a sex offender.
A Gwent Police spokeswoman said a crowd of up to 60 people gathered at around 4.30pm and confirmed two people were arrested for public order offences.
A 39-year-old man and 22-year-old woman were given fixed penalty notices.
Caerphilly Observer understands the crowd believed Michael Forbes, himself of Aberbargoed, was at the address, but he was sent to prison on August 29 at Newport Crown Court.
The 60-year-old was sentenced to 16 months in prison for making and possessing indecent images of children and viewing extreme pornographic images.
Forbes was also given a 15 year Sexual Offences Prevention Order that limits his internet access and prevents unsupervised contact with children under 16.
He was also put on the Sex Offender Register for ten years.
An eyewitness said 11 police vehicles were at the scene.