I mean, once you have been detected, can you escape from the guard? and in that case, how many time do you need to be hidden before they stop looking for you?

You can. The problem is that once you've escaped and hidden from them for a while they will always remain alert.

I didn′t know that. I thought that after a while they stop looking for you

They stop but they stay alerted. Not like in most other stealth games where they completely forget about you like you where never there. Or like in Skyrim. I instakill someone with a headshot from my bow. They become alerted for a while and after a few moments they give up and say: "Must have been the wind.". Yeah, of course, what else could it be...

LoL !! yes, i remember those moments

Nice.

I'm really fed up with other games that have "stealth" (just like Skyrim) where you kill half group, the others search for you for a while and then they completely forget something even happened.

Good thing Dishonored won't be like that.

Good thing Dishonored will be a good game.

*looks at person with arrow through his head on the ground*

Guard: Must have been the wind