There was a spate of such break-ins during 2012, hitting churches in the Marches area, such as Gloucestershire, Herefordshire and Monmouthshire, Wales, but for most of last year there were none, although areas elsewhere in the UK have been affected.
Around November, however, the top half of the effigy was taken from St Mary's Church, Foy, Ross-on-Wye, Herefordshire. The series of thefts actually began in January 2012 when the bottom half of the same burial stone was stolen.
Sally Badham, who was president of the Church Monuments Society from 2008-13, said: "Most of the monuments taken have been connected with heart burials, a specific type of monument. It doesn't sound like an opportunist theft. I may be wrong but they could have been stolen to order for a collector who is interested in church monuments."
The coffin-shaped slab is 3ft 6in (1.1m) in length and shows an unknown female figure in low relief. West Mercia Police said anyone with information on the Foy theft should call 101 or the anonymous Crimestoppers charity on 0800 555 111.