First off, welcome to the board. I'd suggest finding its tracks and try to verify what it is by looking at them first. If it is as big as you say, the tracks should be very noticeably larger than a coyotes tracks. Then, if you can verify that the tracks are huge, compared to a coyote track, contact your local GW again, and have him/her come out and have a look see for themselves, and go from there. It's kind of like reports of mtn. lion in Ks., Fish and Game won't admit to having any around and until you have solid proof, they never will admit to it.