A horse died and seven others escaped across a main road after being chased from their field in Frankley, Birmingham.
The gang of youths are believed to have cut through fencing and removed wooden posts before chasing the horses out of their field, through wasteland and across a main road.
Seven of the horses escaped unharmed but one, Buster, ran into 8ft high metal railings, which surrounded a local school.
Buster, a 12-year-old warmblood, sustained severe damage to his legs and had to be put down. Fire engines, police, a vet and an RSPCA inspector all attended the scene.
Sgt Andy Chinn from Redditch Police Station said: “We are taking this very seriously indeed as it ended with the death of one of the eight horses. There was damage to fencing, which resulted in the horses leaving the field, and we have recorded the crime as criminal damage.
“We are in liaison with West Mercia police to try to establish a motive for the attack
“We would like to appeal to any witnesses who may have any information at all of the incident, or saw any suspicious behaviour around that area on Saturday 26 May.” Nichola Gregory, spokesperson for the BHS, gave the following advice to all horse owners:”Check your fencing regularly and ensure it is always kept in good repair because horses do get out and will find any weaknesses.”Anyone with any information about the crime is asked to contact Sgt Andy Chinn at Redditch Police Station (tel:01527 584888)