The two men said they were collecting for a legitimate cancer charity.
But they could not provide any proof when challenged – and now North Yorkshire Police are investigating.
They have released CCTV images released of two men they would like to speak to regarding the suspected bogus charity collections.
On Thursday January 18 and Friday January 19 the two men pictured were collecting donations for Cancer Research UK in the Marks and Spencers store on Pavement in York.
They were dressed in Cancer Research UK branded tabards and carrying branded buckets.
When questioned by store staff, the men could not provide the relevant paperwork required to legitimately collect in the store.
When store management checked their identification with Cancer Research UK, the charity confirmed that the men were not known to them.
Anyone who recognises the men pictured, or anyone with information which could assist the investigation is asked to contact the police – details below.