Police are seeking a person who threw a litter of kittens at a moving train, leaving one dead at the side of the track in Norfolk.
It happened just before 5.20pm on Thursday, September 15 near Lingwood station on a foot crossing, British Transport Police said.
The driver of the Norwich-to-Great Yarmouth train said he witnessed the kittens being thrown from undergrowth close to the railway line.
Officers found one dead kitten and a dead cat, which had died before the incident.
Two of the four kittens rescued have since been rehomed by Foxy Lodge Wildlife Rescue in Hemsby.
Police Sergeant Alan Bowell said: “This was a truly horrendous and shocking incident.
"No animal should ever be subjected to such cruelty. I am very keen to hear from anyone who might have information which can help us investigate the circumstances surrounding this incident.”
A spokesperson from the RSPCA said: "This sounds like a horrific incident for these poor kittens.
"Deliberate cruelty to animals is unacceptable and we would urge anyone with any information about this to come forward and contact the British Transport Police as soon as possible."