I'm not an expert, but I'm guessing a rescuer has gear that matches the function of a
rescue harness as part of his/her outfit and is wearing it at all times on the job.
A harness is something you can quickly and conveniently strap onto someone else.
As far as I know both the rescuer and victim will be in a harness, the rescuer having the more beefy version as Scotts pointed out. I would put money on equipment failure or a rigging mistake. Very tragic. God Speed to the officer.
Horribly tragic. Hate to keep stressing this point, but this is a reminder to all of us that when we do something risky in the wilderness, we don't just put ourselves at risk. No hike or climb is worth another person's life.
Q: How many therapists does it take to screw in a light bulb? A: Only one, but the light bulb has to want to change ...