I'll add one other thing. I can't imagine what the family is going through right now. IF it were my daughter potentially in the water, I would NOT appreciate having the police announce the possibility on a Thursday night and then state that they probably won't go back until Saturday.
Why not just quietly tell the family, unless they really are trying to smoke out the killer?
Prayer for the family.
If it was my daughter I would have been on the phone to the Mayor, Council members and gotten on a talk show demanding they finish the search today. This is total BS putting the family through this. That "object" could be any thing.