USA - need advice, got searched

[AetherPoison]

Swim needs some serious advice. swim was in his vacation house in Maine (U.S.) with his friends packing a bowl in swim's bathroom. swim hears a noise outside the door and opens it to find the cops (unanounced) pointing a gun at him and telling him and his friends to exit the bathroom. they had recieved a call from the neighbors about a break in (they thought swim broke in) but swim clearly stated that he was on his own property and nothing was wrong. the police then proceeded to enter swim's bathroom to find weed and a pipe which they confiscated (this was swim;s friends, not his own so he was not charged for this.) the police then told swims to sit down and searched swim and his friends. they found rolling papers in swim's wallet and gave him a summons to court for having paraphonalia (in maine its considered paraphonalia in the proximity of weed i guess)
They then made a call to the town confirm that this was indeed swim's house. since the house was bought not too long ago it was not registered in swim's name, but they called his parents and confirmed ownership.

now swim must go to court for drug paraphonalia, and his friend for possesion and paraphonalia. Now swims question is: is what they did legal? may police enter a house unnanounced, and search swims bathroom and persons and charge for what they found when swim is legally on his own property? any help would be appreciated swim doesnt have the money for a fancy lawyer