Police are investigating after three cows were killed at a farm in Ashton-under-Lyne.
It happened between 9pm on Tuesday, March 17, and 6.30am the following day.
Greater Manchester Police said the offenders walked into the cowshed of a farm near Lees Road.
Three cows received stab wounds and were killed.
Another nine were seriously injured and had to be destroyed.
Officers are linking this attack to an arson at the same farm between 12am and 2am on Sunday, March 15.
- Anyone with information should phone police on 0161 856 9260 or Crimestoppers on 0800 555 111.