P.R. Laws Ap. tit. 34A, § II, Rule 128
The clerk shall read the information to the jury, and state the plea of the defendant. If it charges a previous conviction and the defendant has confessed the same, the clerk shall omit therefrom all that relates to said conviction. The prosecuting attorney shall open the case stating orally to the jury or to the court, as the case may be, the nature of the offense which he expects to prove, the circumstances under which the crime was committed, the proofs which he expects to produce for upholding his charge or complaint, and shall gather and offer his evidence in support of said information or complaint. The defendant shall then set forth in a concise manner the proofs for his defense and shall offer and produce his evidence in support thereof. The prosecuting attorney and the defendant may then, in that order, offer rebutting testimony only against the evidence originally offered, unless the court, for good reason and in furtherance of justice, shall permit them to offer evidence upon their original case.