How does the wife know she has rescued her husband’s killer?

In the movie Hunter Hunter, the wife rescues a stranger, nursing him and feeding him before going out to look for her missing husband in the forest. Then she finds her husband’s dead body with a head wound.

She suddenly realises she has rescued her husband’s killer. How does she realise it? The only correlation between her husband’s murder and the stranger she rescued is perhaps the fact that she estimates her husband was killed roughly moments before she found this wounded stranger.

But this correlation is pretty weak.

Any other thoughts?