What to do about a good friend that is a repeat suicide risk?

I have a good friend who has been diagnosed with bipolar disorder. He is also a struggling alcoholic. He has attempted suicide in the past and has also been hospitalized. His new love interest is anti drinking and as a result of him drinking she is shunning him. He is in a downward spiral right now and keeps making hints through ims and tweets about killing himself. Someone reported him earlier and a state trooper came to his house. The hints keep coming. What can I do?