Police are appealing for help in finding a person who threw kittens at a train near Norwich in a "truly horrendous" incident.
A train driver reported seeing a person throw the kittens from undergrowth at a foot crossing near Lingwood station.
British Transport Police officers attended the scene and found a dead cat along with one dead kitten.
The cat was thought to have died some time before the incident, and four other kittens were recovered alive.
They were taken to Foxy Lodge Wildlife Rescue in Hemsby, near Great Yarmouth, where they were treated by vets for cuts.
So far, the rescue centre has been able to rehome two of the kittens.
Sergeant Alan Bowell said: "This was a truly horrendous and shocking incident.
"No animal should ever be subjected to such cruelty.
"Thankfully, not all the kittens were killed during this dreadful ordeal and are being well looked after."
The incident was seen by the driver of a Norwich to Great Yarmouth train service shortly before 5.20pm on Thursday September 15.
An RSPCA spokesman urged witnesses to contact British Transport Police with information.