A Perth family who lost their pet alpacas to a horrific dog attack believe the perpetrators were engaging in blood sport.

Elle Callo and her mother Nadine were woken late on Wednesday night by the barking of her own dogs and sounds of distress from her alpacas.

The Callo family had the alpacas as pets. Credit:9 News Perth

After racing to a window they saw a black shape dart for the fence line of their Hazelmere property.

Looking hard, they saw it was a dog which was following two men wearing Hi-Vis clothing who jumped into a ute that drove away with spotlights blazing.