A detective investigating the theft of a historic diamond-encrusted tiara and a diamond brooch from an art gallery in Worksop has appeared on BBC One's Crimewatch Roadshow Live to re-appeal for information.
Detective Inspector Gayle Hart was on the show on Monday morning and urged witnesses to come forward.
The historic Portland Tiara and diamond brooch were stolen from the Portland Collection Gallery on the Welbeck Estate between 9.45pm and 10pm on November 20 last year.
Officers arrived at the scene within minutes of the burglary being reported but the offenders had fled in a vehicle.
Speaking after the programme DI Hart said: "We're still determined to find the people responsible for this brazen theft but we need the public's help.
"I hope that by appearing on Crimewatch Roadshow and renewing our appeal it may jog someone's memory to come forward with information - no matter how small.
"We're still pursuing a number of lines of enquiry but we believe there are people out there who may have crucial information that could help with our investigation.
"We particularly want to hear from anyone who has any information about a silver Audi S5 which is suspected to have been involved in this offence.
"This vehicle was found abandoned and burnt out in Cross Lane, Blidworth, about half-an-hour after the incident.
"If you have any information about this vehicle we'd urge you to please come forward and contact us as soon as possible.
"We'd also like to hear from any drivers who may have dash-cam footage of this vehicle.
"We're asking people to please call us on 101, quoting incident number 856 of November 20, 2018, or Crimestoppers anonymously on 0800 555 111."
Police arrested five men, aged 47, 39, 38, 34 and 24, and a 31-year-old woman in connection with the ongoing investigation.
All six, who were arrested on suspicion of conspiracy to burgle, have been released under investigation.
A private appeal, offering a reward of up to £100,000 for information leading to the recovery of the Portland Tiara and diamond brooch, is being administered by the Art Loss Register.
If you missed the Crimewatch Roadshow programme, you can still watch it on BBC iPlayer.