I shoot anywhere from 12 to 24 'coons a year after calls from citizens such as what you reported. A few years ago it was worse, when disease ran rampant through the 'coon population. You have to look at the overall actions of the animal, its demeanor as you try to approach it, and the appearance of the animal. The sick ones look pretty mangy ( no self care), don't retreat or even acknowledge that you are there, and their ambulatory functions are greatly impaired when they do try to walk away. Around here, we don't save the body unless its bitten someone...if you or someone is bitten, the animal needs to be destroyed in whatever way best preserves the brain for examination for rabies.BTW, there is now a preventative vaccine for rabies thats much less painful than the post-bite shots you get; I get it every 7 years due to the volume of contact I have with these animals....if no one has been bitten, double bag the carcass and toss it in the dumpster for disposal. We used to tell people to bury them, but no one was digging the holes deep enough, and wild animals would dig up the carcass.....