Identify mystery bugs in the compost

Q: This morning, after a long, hard rain, I went out to my garden and found many worms in the wet dirt. For the first time ever I also found two long, skinny, black, hard-shelled bugs with tiny legs (almost like black, hard-shelled earwigs) attacking two worms. The worms were thrashing around until I killed the two black bugs. I am worried because I use my own compost on the garden and last year I counted far more worms in my compost and in my garden than this year. Any idea what the bugs are and if I should be really concerned?

Without a picture to verify, I believe the insects are probably beneficial insects called “Rove Beetles.” This beetle tends to be elongate in form with very short wing covers. They prey on insects found in soil such as aphids, springtails, mites, nematodes, flies and cabbage maggots. They also help in decomposing organic matter, especially around compost piles and gardens. Over 3,100 species of Rove Beetle are believed to be native to North America.