Gwent Police
Gwent Police officers handcuffed the 29-year-old despite not being under arrest, the Independent Office for Police Conduct said.
Two people have also been injured after incident in Monmouthshire, Gwent Police confirms.
Gwent Police are investigating allegations that some care home staff are victims of modern slavery.
Gwent Police said the comments at a Brexit Party rally in Newport did not constitute a criminal offence.
Dozens of people have complained to police after a video of Farage at a Brexit Party event in Newport surfaced on Saturday morning.
The teenager was found in Ystrad Mynach park, south Wales.
Two women involved in the crash received 'potentially life changing injuries'.