Do cops have to say they are cops when they knock on your door.

heres what append.

i was in college at Florida State University and asleep in my dorm room. I am awoken by a knock on the door and ask "who is it?" without getting out of my bed or looking through the peep hole(big mistake)

the cop said, "Tom." and as i have many friends by that name i opened the door a crack to see who it is.

obviously i see that it is cops and try to close the door. they ask if they come in and i say quote, "in a minute after i put some clothes on."

the cop then puts his hand on the door and says, "I'm not going to let you close this door."

him and his partner then proceeded to search my room and found a large amount of liquid LSD and a small personal amount of marijana.

apperently eariler in the night some people i had given some of the LSD to were causing a large disturbance on campus(running around naked) and were questioned by the cops and told them they got the drugs from me which is how they knew to come to my room.

however they did not have a warrant as this all happened in the course of a few hours.

one of the kids unsucecfully tried to jump out a window so the cops took the situation as a serious saftey risk and decided to act without a warrent.

My lawyer is telling me its a tricky situation because on one hand it does sound like an illegal search but on the other hand the cops could just say that i would have sold to more kids and people may have died had they not arrested me.

I don't know if they consulted the RA's or any school officials prior to the search but i do know that their were only 2 police officers at my door and they are the only people who searched my room.

the mandatory minumum sentance that i could be looking at is over 15 years but the state prosuctor is offering me a decent plea bargain probibly because he knows its a **** case.

I could get off with reduction of charge to a misdaminor but i'd still have to do a couple months time and be on probation for at least a couple years.

are their any legal precedents for cops having to announce that they are cops when they knock on your door if you ask who is is?

are dorm rooms just completely fair game when it comes to illegal searches?

please help.
thank you.

just to clarify one thing. in the police report the cops specificlly state that they smelt the marijuana ONCE THEY ENTERED THE ROOM, BUT NOT BEFORE THEY CAME IN. So theirs no probable cause from that