Police are investigating allegations that an officer repeatedly punched a teenager with autism, after a film of the incident was posted on social media.
The film appears to show two police officers shouting at a young man, before pushing him to the ground, while one of the officers seems to punch him four times, and the other tells him to put his hands behind his back.
The teenager, named by local media as 17-year-old Tristan Perry, is heard saying: “Why are you punching me?”
The film was apparently shot by a friend of Perry, who was with him at the time of the incident in Northampton on 13 August.
Perry’s mother reportedly plans to send the film to her son’s social worker.
The incident has been referred to the Independent Police Complaints Commission (IPCC).
Assistant chief constable Rachel Swann, of Northamptonshire police, said in a statement: “We are aware of a short video circulating on social media allegedly showing Northamptonshire police officers.
“We take such allegations extremely seriously and immediately referred the matter to our professional standards department as soon as we became aware of it.
“An investigation is currently underway and, as such, it would be inappropriate for us to comment further while this takes place.”
A spokeswoman for Adam Simmonds, the police and crime commissioner for Northamptonshire, said he had not seen the footage, although he had “seen some stills of it”.
She said: “He isn’t commenting on the incident at this stage as it is an operational matter which is very much under investigation.”
But she added: “All of our officers (and staff in front line roles) have taken part in a course aimed at raising awareness of vulnerable people, reinforcing what actions should be taken to protect people as well as how to work with people with different needs.
“This is in addition to their basic training and will be repeated regularly.”
A spokeswoman for Northamptonshire social services said: “We would not really give you any detail on it because it is a police investigation at the moment.”
The film emerged as the IPCC confirmed that two police officers from neighbouring Bedfordshire police would face allegations of misconduct and gross misconduct at a public disciplinary hearing, following an alleged assault on a man with autism.
An investigation was carried out by Leicestershire police – on behalf of the IPCC – into the incident in February 2014 in which Faruk Ali was allegedly attacked as he returned wheelie-bins to the front of his own and his neighbours’ homes in Luton, as he did every Thursday morning.
The two police officers were acquitted last December after a trial on charges of misconduct in a public office and perverting the course of justice, while one of the officers was acquitted of racially-aggravated assault.
Meanwhile, a report commissioned by the home secretary has found that up to 250,000 people with learning difficulties, mental health conditions or autism are not receiving the support they are entitled to when detained or questioned by police.
The legal requirement for police to provide an “appropriate adult” to accompany disabled people with certain impairments who are detained or questioned by police was introduced in the 1980s, following a series of miscarriages of justice.
An appropriate adult is supposed to ensure “effective communication, welfare, understanding, fair treatment and helping people exercise their rights”, including the right to see a lawyer.
The report by the National Appropriate Adult Network, There To Help, shows appropriate adults are currently only used in about 45,000 of the 1.4 million detentions and voluntary interviews of adults each year, despite an estimated 280,000 involving a person who is seen as “mentally vulnerable” under police regulations.