British Transport Police are appealing for information after a suitcase was stolen from a train in Grantham.
The suitcase is said to have been grabbed by a man who left the train as it arrived into Grantham at 5.52pm on August 2.
The man suspected of the theft is believed to have travelled from Peterborough.
Officers believe the man pictured may be able to help with the investigation.
Anyone who recognises him should text British Transport Police on 61016.