The hoglet, which weighted just 150g, died earlier this month after it was rushed to Castleford Hedgehog Rescue.
A member of the public said they had seen two boys kicking the animal while a girl poured water over it on Thornhill Road, Castleford, on Saturday, June 29.
Fay Vass, Chief Executive of The British Hedgehog Preservation Society said: “This is a cowardly and sickening act. The pain and fear the poor hedgehog must have gone through is heart breaking.
"We thank Castleford Hedgehog Rescue for all their efforts to save this little one and the Police for acting so quickly, we urge anyone with information about the attack to report it immediately.”
The British Hedgehog Preservation Society is offering a reward of £1,000 to anyone who supplies information that leads to a successful prosecution of those responsible.
A spokesperson for Castleford Hedgehog Rescue said “When the hoglet arrived we were told the story and our hearts sank, we couldn't believe what we were hearing, this poor innocent little baby was being drowned and kicked to death by these three kids and being so close to our rescue we battled so hard to keep her going but she passed away.”
Anyone with any information on the incident is asked to contact West Yorkshire Police on 101, quoting crime number 13190340664.