The fourteenth juror in the trial of the three men accused in the slaying of Andrew P. Puopolo '77 was selected yesterday leaving two more still to be chosen.

The selection process adjourned without filling the jury because the court had exhausted the pool of available jurors, a spokesman for the Suffolk Country Superior Court said yesterday. Attorneys in the case estimated that the court has considered between 130 and 165 potential jurors so far.

The defense and the prosecution may excluded up to 48 jurors each in addition to those the Judge excuses for possible bias.

The defense has only one remaining of these pre-emptory challenges, while the prosecution has nine remaining.

Henry F. Owen III, a defense attorney in the case, said he felt that potential jurors who were either Irish Catholics from South Boston or Italians from the North End would be biased against the defendants. He added that the defense has so far been able to exclude members of these ethnic groups from the jury.

Sympathetic

Owen also said the chief prosecutor, Assistant District Attorney Thomas J. Mundy, was trying to exclude blacks from the jury because they would be sympathetic to the defendants.

He added that out of 13 potential black jurors, all but one were not excluded.

Assistant District Attorney Ira Wallach declined to comment on Owen's charge.