An elderly stamp collector whose £80,000 collection was stolen during a raid on his home has put up a reward for its return.
The victim, from Presteigne, Powys, who does not want to be named, spent 60 years building up his collection, which included several rare examples.
Some of the stamps were recovered when two people were charged and then jailed for theft at Merthyr Crown Court.
But many are still outstanding and the owner is appealing for their return.
Dyfed-Powys Police said they believed other people were involved in the theft and were holding the missing stamps.
The raid happened in Presteigne at the beginning of December 2009, and to date only small quantities of stamps have been recovered, said officers.
Police said two people were arrested and charged with the theft of some of the stamps. They were both recently jailed for a nine-month and two-year term at Merthyr Crown Court.
Pc Melanie Rossiter said: "It is believed that the remaining stamps are held locally, and I am appealing to people who may have information regarding the whereabouts of the stamps to contact Dyfed-Powys Police.
"This stamp collection was a life-long hobby for the victim and compiled over more than 60 years. The collection was not only financially valuable but more importantly were of huge sentimental value to the victim.
"In addition, I would also like to reassure the people of Powys that these types of crimes are very rare."
The stolen stamps include quantities of rare penny black, penny red and two penny blue stamps.
The victim has not revealed the value of the reward.
People with information leading to the conviction of the offenders and safe return of the stamps are asked to contact Dyfed-Powys Police on 101.