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.

If the allegations in the information are vague and ambiguous, the accused, before arraignment, can move for a bill of particulars to enable him to prepare properly for the trial.


 What is the purpose of a bill of particulars?

 It is to enable the accused to properly plead and prepare for trial.

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)
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)