When you're out wandering Skyrim's woodlands, with seemingly none to see what you're up to, you might fall into the trap of believing there are none who can spot you commit a crime. Whether it's killing a random NPC as part of the Dark Brotherhood questline, or stealing a sweetroll, there's always at least one secret agent looking out for all crimes.
According to the unofficial Elder Scrolls Wiki, it's not only humanoid eyes you'll have to watch out for when committing a crime, as animals - including your own horse - can spot you and report you to the guards, increasing your bounty within a Hold.
This means you'll have to kill surrounding animals as well as people if you wish to exonerate yourself fully. It's quite a dark realisation, and a silly one, when you start to wonder how a horse could inform anyone of you killing a man deep in Skyrim's woodlands.
Were you aware of this Skyrim secret?