Police have released these photographs after a theft from a North Yorkshire train.
It happened at around 4pm on Monday 27 July.
A man stole a suitcase from the luggage rack and left the train at Northallerton railway station with it.
The suitcase and its contents had a combined value of nearly £1,500.
Officers believe the man in the image could have information that may assist their enquiries.
Anyone who recognises him is asked to text BTP on 61016, or call 0800 40 50 40, using the reference 2600097807.
Information can also be given anonymously to Crimestoppers via the web or on 0800 555 111.