The constabulary is aware of footage of the incident circulating online
Isle of Man Constabulary says it will continue to work with marshals to prosecute those who enter closed roads during racing.
During last night's (19 August) qualifying session, officers received reports of a man crossing the course at St Ninian's traffic lights.
In a statement, the constabulary says it's aware of footage of the incident circulating online and is being assisted with enquiries by a local male.
It adds entering a closed road is dangerous and illegal as it places lives at risk, and the evening could have ended horrendously.
Rider dies following MGP qualifying incident
Four freed from car after Foxdale crash
‘Cover-up’: Details of ‘peaceful protest’ at prison disputed
Castletown Commissioners brands Market Square vandalism an 'act of stupidity'