There is some confusion 'concerning' [='regarding'] his current whereabouts.
news 'concerning' friends
(..) I stole that because of you. I spied on my own because of him. Do you know how that makes me feel? Ricki... you said you sent the Circus a telegram concerning Irina's information. - That's right. - What was the date? He doesn't know because there was no telegram. - The whole thing is a fabrication. (..)2011 Tinker Tailor Soldier Spy
(..) Well, I understand how you felt. You wanted to do something. Vital to the safeguarding of the Circus. Anything more? I said that she had information concerning a double agent. Look, I just wanted to get the proper attention. And I'd... I told them this was the reason why I had not come home. (..)2011 Tinker Tailor Soldier Spy