A pair of ladders may help find thieves who broke into Arundel Castle and stole historic artefacts worth more than £1m.
Gold and silver items stolen from the historic Sussex landmark last month included an “irreplaceable” set of rosary beads carried by Mary Queen of Scots at her execution in 1587.
Police have released images of ladders used by the gang to break into the castle.
Detectives hope the owners of the paint-splattered steps will recognise them and come forward.
The stolen artefacts were described as of “priceless historical importance” following the raid on the night of Friday, May 21.
Officers arrived at the West Sussex castle within minutes of being called by staff who were alerted by a burglar alarm at about 10.30pm.
Police say the ladders had been used to access the dining room area where a window was forced to gain entry. One of the ladders is 6ft long, the other 12ft, but both are capable of being extended to twice their lengths
The stolen haul – which also included several coronation cups given by Mary to Earl Marshal – were taken from a display cabinet in an area of the castle that is usually open to the public.
Detective inspector Alan Pack, of Sussex Police, said: “The ladders have clearly been well used over some years.
“The long ladder has distinctive black and yellow paint splashings and each has some worn labelling.
“We hope that someone in the decorating or building trade, or maybe someone who just had them at home, will realise that they are now missing them, and will contact us.
“If you recognise them, please contact us either online or by calling 101, quoting Operation Deuce.
“In addition, if you were in Arundel and saw any suspicious activity around the area of the castle, either that evening or in the previous few days, as the castle only re-opened to visitors on Tuesday, May 18, please let us know.
“If you are offered or hear of anyone offering for sale any of the items stolen, we would also like to hear from you.”
TV historian Professor Kate Williams, of Reading University, said in the wake of the castle burglary that most of Mary’s belongings had been “despoiled” or burned following her execution.
She added: “We had one tiny memorial of Mary Queen of Scots – and now it has gone.”