Investigate
Tone
You say something about the circumference of this area. You've looked around this whole area, making a big circle around it, because you are trying to investigate something that happened here. You also say this thing in a really quiet tone of voice, because you don't want the person or thing you're investigating to know you're on to them.
ちょう
しら
None
"I came here to investigate this place, and I did indeed find out who the criminal is... it's none other than Mrs. Chou (ちょう)!"