Police say the motorcycle used in the jewellery robbery was stolen from the Tynwald Street area of Douglas and was ridden down Westmoreland Road towards Circular Road around 4pm on Friday.
Detective Sergeant Richard is asking for anyone who saw the motorcycle or the rider shortly before 4pm to come forward to help with the ongoing investigation.
The motorcycle was recovered from the rear of Belmont Terrace later on Friday evening.
The police are particularly keen to speak to anyone who was either walking or driving down the lane behind Belmont Terrace just after the time of the robbery.
Earlier the police also confirmed that they have now identified the man who gave chase to the jewel thief after leaving RHS jewellers and they had a 'very good response' to the CCTV pictures showing a man leaving the crime scene riding an off road motorbike, wearing a distinctive crash helmet, black jacket and jogging trousers.
If no arrest is made over the weekend its expected further CCTV pictures might be released to the media on Monday.
See more at on MTTV