Section 9. Bill of particulars. — The accused may, before arraignment, move for a bill of particulars to enable him properly to plead and to prepare for trial. The motion shall specify the alleged defects of the complaint or information and the details desired.  (Rule 116, Rules of Court) 
What is a bill of particulars?

It is a more specific allegation. A defendant in a criminal case who believes or feels that he is not sufficiently informed of the crime with which he is charged and not in a position to defend himself properly and adequately could move for a bill or particulars or specifications. If he does not do so, whatever vagueness there may be in the allegations may be cured by evidence.


 What is the purpose of a bill of particulars?

 To apprise the accused clearly of the charges filed against them, and thus enable them to prepare intelligently whatever defense or defenses they might have. (People vs Abad Santos, G.R. No. L-447, June 17, 1946)
What is the reason for allowing bill of particulars?

 In criminal cases, any defect in the accusation other than that of lack of jurisdiction over the subject matter may be cured by good and sufficient evidence introduced by the prosecution, and admitted by the trial court, without any objection on the part of the defense, and the accused may be legally convicted of the crime or offense intended to be charged and so established by the evidence.

Of course, it is to be expected that the defense will object to any question, which is not based upon the allegations made in the complaint or information; but this does not preclude the possibility that immaterial evidence might be admitted, although not supported by such allegations, due to inadvertence on the part of the defense. And inasmuch as in criminal cases not only the liberty but even the life of the accused may be at stake, it is always wise and proper that the accused should be fully apprised of the true charges against them, and thus avoid all and any possible surprise, which might be detrimental to their rights and interests; and ambiguous phrases should not, therefore, be permitted in criminal complaints or informations; and if any such phrase has been included therein, on motion of the defense, before the commencement of the trial, the court should order either its elimination as surplusage or the filing of the necessary specification, which is but an amendment in mere matters of form. (People vs Abad Santos)
When can the accused move for a bill of particulars?

 The accused must move for a bill of particulars before arraignment; otherwise, the right is deemed waived.
What should be contained in the motion for a bill or particulars?

 It should specify the alleged defects of the complaint or information and the details desired.


Is the provision on bill of particulars applicable when the case is still in the prosecutor's office for preliminary investigation? 

No. The procedural device of bill of particulars appears to have reference to informations or criminal complaints filed in a competent court upon which the accused are arraigned and required to plead, and strictly speaking has not application to complaints initiating a preliminary investigation which cannot result in any finding of guilt, but only of probable cause. (Cinco vs Sandiganbayan, G.R. Nos. 92362-67, October 15, 1991)
What is the remedy against an indictment that fails to allege the time of the commission of the offense with sufficient definiteness?

The remedy against an indictment that fails to allege the time of the commission of the offense with sufficient definiteness is a motion for a bill of particulars. (Rocaberte vs. People, G.R. No. 72994, January 23, 1991)