I thought so at the time and again when I read the transcript. Since I believe Greta's style would have been to get a lot more details (like who called him, what phone call they listened to, who was the young man in his car, etc.) I tend to think that Greta had to agree not to pursue certain questions or he was deliberately vague. (Which brings to mind Twittys and the information they don't want to reveal at this stage.)
I think you're right.