Saguaro cacti have been slashed or chopped up along Gould's Mine Trail at Saguaro National Park West.
There are at least eight saguaro cacti that are damaged along the trail.
The damaged cacti are about a 20-minute hike from the starting point near the Sonoran Desert Museum.
Cuts to the cacti were all straight and clean.
"That's pretty horrible because we love our cactus, we love our saguaros," said Esther White, a hiker.
This is similar to incidents from 2013 at Saguaro National Park East. Saguaro cacti were spray painted with graffiti early in the year. Later, a handful of cacti were cut down or knocked over. Two men admitted to that second incident and were asked to pay for restoration but could have faced federal criminal charges.