I had the same problem a few years back, found more than potatoes when digging.
Built a cat trap and smoked oyster oil in the tin at the back of the trap.
Cat goes in, bumps the stick, gate goes down.
Cat sits on the back of truck in driveway in trap tailgate down making a lot of noise for everyone to see/hear for a couple hours.
Cats can make a hell of a lot of noise.
Cat makes a trip to were i know the coyotes are thick.
After the third cat all the rest seemed to be kept in their house not shatting and roaming freely about.
Then I cleaned out the flower gardens for the missus.
