Sussex Police is redoubling efforts to secure information about silverware worth £100,000 stolen from the University of Sussex's sacristy at Falmer, near Brighton. They are still trying to locate the missing items and to trace the man thought to have stolen them.
A £10,000 reward put up by the university for help in solving the case remains on offer.
Detectives now think the thief may have links with Birmingham, Wolverhampton and Wiltshire, and have extended their appeal for information accordingly.
The theft happened between 1.50pm and 2.20pm on Friday, 7 December.
Closed circuit television images from security cameras suggest the man shown here may be able to help with the investigation.
Anyone recognising him or who knows where he might be, or who has information about the missing items, is urged to get in touch without delay.
Locked doors and containers were forced open to steal the valuables, which included two silver chalices by noted sculptor Hans Coper.
They are thought to have been placed in a black rucksack before the thief made off on foot towards the university's Pevensey block. It is possible he then boarded a bus or got into another vehicle.
The suspect is described as a man in his 30s, of mixed race, 6' tall and of medium build, bald and with facial stubble.
He was wearing a blue Puffa-style jacket over a grey hooded top, grey tracksuit bottoms and trainers with white markings on them.
Dealers have been alerted to the theft and asked to report any suspicious transactions.
Detective Constable Rowan Carter, investigating, said: "More than six months have passed since the theft, but we remain confident that someone, somewhere has the vital clues we need to recover the stolen items and bring the offender to justice."
Anyone able to help is asked to contact Sussex Police online or by phoning 101, quoting serial 806 of 10/12/2018.
Alternatively, details can be reported to the independent charity Crimestoppers online or by phoning 0800 555 111.
Advice on crime prevention can be found here.