Police have confirmed that a marshal and rider died in Tuesday evening's Southern 100 practice session.
A statement released by the Constabulary on Wednesday morning said: 'Around 7pm on Tuesday, July 11 an incident occurred during the Southern 100 which tragically resulted in the death of both a rider and a marshal.
'This occurred in the area between the start line and shortly after the junction of the bypass with Arbory Road.
'Owing to the nature of what has occurred, the area of road between the traffic lights at the Malew Street bridge and Ballakaighin Corner remains closed, along with a short section of Arbory Road. This is to allow for forensic work to be fully undertaken by officers from the Constabulary’s collision investigation unit.'
Detective Inspector Neil Craig can confirm that both the rider and marshal who were killed in this collision were males, but no further details as to their identities is being released at this time.
DI Craig said: 'The area was well attended at the time by members of the public who were watching the races, and officers have already spoken to a number of people regarding what they saw.
'However, it is likely that there are people who either witnessed what occurred, or who have video footage of the incident itself, who we are yet to identify and make contact with.
'I would therefore like to appeal to anyone who was present at the time, and who feels they may be able to assist, to please make contact with us in the first instance at police headquarters on 631212.'
Any witnesses, or people affected by the events of last night can attend Castletown Civic Centre where police and staff from Manx Care will be present to provide any help and support you may need.
The Centre can be found directly next door to Castletown Police Station, just off Castletown Square.
Whilst investigations are still being undertaken into this collision, we would respectfully ask the public to refrain from speculating as to what may have occurred.