The best way to resolve a dispute, it is said, is to have a dialogue/discussion among the parties.
My sugegstion to you would be for the three remainig partners to discuss a plan of action and then talk to the misbehaving partner on what you wish to do. In your case, the most likely action plan would be to remove him from the partnership. You may give him a little more than what may be his share (since you would save soem time, effort and money by not going thorugh the legal process.)
If the partnership clause does not provide for removal of a partner, you may also include it by discussing with the 4th partner but remember that this caluse can also be misused by the majority of the partners coming together to remove one partner.
He may agree to your plan but if he does not then you have to prove his misbehaviour and fight it in the Court.
Adv Bharat has stated it nicely - you will have a joint and several responsibility for each other's acts as partners as long as you are partners.