I went to the specialist shop near my place (Atelier Bière et Vin - Mtl South Shore) and they helped me with this mystery. Actually, they told me to do something REALLY obvious: re-take the density!
Before the filtration it probably was krausen.
After the filtration, I stirred up some of the sugar from the strawberries and the fermentation took off again. Although I put clarifying agents in it... I must admit that I may have been a little cheap with them :P
The density went from my wrong final reading of 1.004 to 1.000.
Now that I'm sure that it was fermenting, I let it go for a while but the cider was still very opaque. I filtered it again yesterday and it's now very clear! I'm letting it sit a little before bottling.
Hopefully this will help some of you beginners out there with some similar myterious problems
I had the same thing occur in my first two batches of cider. My instructions said to move to secondary once the cider stopped fermenting. I got two readings of 1.009 three days apart, so I assumed that they were done so we racked to secondary. About three weeks later I noticed new bubbles so I checked the gravity and it had dropped to 1.004. We just bottled this past weekend and it had dropped even further to .996.
We added tart cherry juice to try to get something akin to a Cherry Bomb by Julian and can't wait to see how the finished product turns out. The samples tasted pretty great.