P.R. Laws Ap. tit. 34A, § II, Rule 76
In any criminal prosecution, The People or the defense may request the disqualification of the judge on any of the following grounds:
(a) Where the judge has been prosecuting attorney or counsel for the defendant in the case.
(b) Where the judge is the essential witness in the case.
(c) Where the judge presided over the trial of the same case in a lower court.
(d) Where the judge has an interest in the outcome of the case.
(e) Where the judge is related by consanguinity or affinity within the fourth degree to the defendant, to the victim of the offense charged or to defendant’s counsel or the prosecuting attorney.
(f) Where the judge has a formed opinion or prejudice in favor or against any of the parties, or might have prejudged the case.
(g) Where the judge acted as magistrate for the purpose of issuing the warrant of arrest or summon or for the purpose of determining probable cause at the preliminary hearing.