Mystery Flowers...Another Dead End

So I've been playing the part of a detective over the last week trying to find out who those mystery flowers that were sent on grad were from. The call to the florist came up with nothing. Then on Monday I talked to my prof who had originally told me that the flowers were for me. I thought surely she would know who had dropped them off. It turns out that she does know but that she had strict instructions to keep it a secret. In my mind I thought I had figured out exactly who it was, we'll call this suspect J. This happened on Monday and J was going to be out of the office until today. I thought I would wait and ask her myself when she got back. I knew that there was no way that J would be able to lie to me, she's too honest for that. So today I confronted J and apparently it wasn't her either. She did however have the instructions that had been left with the flowers. She pulled them out of the recycle bin and gave them to me...no real clues there, just some instructions on watering them and a 24 hour freshness guarantee. Another dead end. I did discover that J can pull off a lie for a little while however because at first she told me she didn't know who sent them but as conversation continued it came out that she did know but had also been sworn to secrecy. Now talk about frustrating, two people who know who sent the flowers but they won't tell me who it was! I tried just about everything to get it out of J this morning. I even resorted to bribery! Unfortunately her lips appear to be sealed. Maybe my next plan should be to send in a spy... No one would suspect a question strategically dropped by roommate in passing conversation I am sure! I have been told that my thanks will be passed on to the mystery flower sender, which I am glad for. At least they will know that I really appreciated the flowers. They were a highlight to my special day. I have only received flowers a couple of times in my life and these ones were exceptionally pretty! In the beginning I really just wanted to be able to thank whoever sent the flowers. That is taken care of now through messengers but now it has become more than simply thanking this very thoughtful person...It's a mystery that's driving me bonkers!