Where did the event happen?

W: Lost and Found Office, can I help you?
M: Oh, yes, I’ve lost my briefcase.
W: Would you tell me some details, such as what it looks like?
M: Well... it’s a yellow leather one, a heavy bag.
W: Oh, have you locked it?
M: Unfortunately not, so I am very worried now. If I cannot find it, it would be quite troublesome.
W: Is there any obvious features on your briefcase?
M: The brand name of the briefcase is not famous, but at the bottom of it there is a scratch, quite small.
W: OK, what did you put in your briefcase?
M: Well, some clothes, my passport and some cash, so lucky that I didn’t put these files of my company in it.
W: I have written it down, and where did you lose your briefcase?
M: I cannot believe it, when I was checking in, I just put it next to my leg... after I finished checking in, I found it was gone!
W: What time was it when you found your briefcase was gone?
M: Ah, it was... it must have past 5:30 pm, I remembered I had heard the clock told the hour before I went to the check-in counter.
W: OK, could you tell me the value of your briefcase?
M: I am not sure, well, when I bought it, I paid 57 dollars, but the briefcase itself is not very new, now the value of it is at most 25 dollars, but the contents in the briefcase are worth about 100 dollars at least.
W: OK, would you please leave your contact telephone number here in the form? If we find your briefcase we will call you at once, and we will also put the concerning lost and found information on our network so that you can check it very conveniently. Furthermore, if you have time you could come here.
M: Sorry, I am on my travel, and I will not stay here for a very long time.
W: In that case, we will contact you and post your briefcase to you, but you have to pay the postage.
M: That’s very kind of you.