A man believed to have stolen items from a suitcase at Newark Northgate station may have travelled onto Lincoln, police have said.
British Transport Police are appealing for information after items from the bag was taken by a man shortly before 7.30pm on December 28.
He was travelling on the train between Edinburgh and Lincoln.
The man was seen on CCTV taking a laptop and other items from the case and leaving it in the toilets.
He then caught a train towards Lincoln or London.
Officers believe the man in the image may have information that could help the investigation.
Anyone who recognises him is asked to contact British Transport Police on 08000 40 50 40 or by texting 61016.