A man who is believed to have killed himself on the M4 outside Bristol on Saturday had been arrested recently after being accused online by a self-proclaimed “online child protection team”.

Avon and Somerset police said they had made a mandatory referral to the Independent Office for Police Conduct (IOPC) after previous police contact with the deceased.

The man died on Saturday at about 6.40pm, police said.

The Guardian understands an online group alleges that during a livestreamed video the man attempted to engage in sexual activity with what he thought was a child.

He was subsequently arrested and was released from custody on police bail on Saturday. He had not been charged with any offences.

The group involved in the alleged sting said it had removed the livestreamed video.

In a post online, it said: “Can we please respect his family and allow them to grieve. We did what we had to do and expose a pred, but unfortunately we have no control of what they decide to do following a sting.”

The group told the Guardian it had been operating since September 2022 and claimed to have caught more than 150 individuals who went on to be convicted and sentenced.

The group, which is made up of 10 people, said they would typically contact police when they had confirmed the identity of an alleged suspect, shortly before they went live online.

An inquest will be held into the man’s death in due course.

In a statement, Avon and Somerset police said: “The death is being treated as non-suspicious and his next of kin are being offered support during this difficult time. Our thoughts and sympathies remain with them.

“A mandatory referral has been made to the Independent Office for Police Conduct (IOPC) following previous police contact.” The force added: “We would ask people not to speculate during this time and to respect the family’s privacy.”

An IOPC spokesperson said: “We can confirm we have received a referral from Avon and Somerset police in connection with a man’s death on Saturday evening. We will be assessing the referral to decide whether any investigation by the IOPC is required.”

• In the UK and Ireland, Samaritans can be contacted on freephone 116 123, or email jo@samaritans.org or jo@samaritans.ie. In the US, you can call or text the National Suicide Prevention Lifeline on 988, chat on 988lifeline.org, or text HOME to 741741 to connect with a crisis counselor. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at befrienders.org