Obstruction of justice case

Hello Attorney, if there's a murder case and you cannot pursue it because someone intentionally holding the documents and evidence which is the cause of the victim's death, would this fall on obstruction of justice? They intentionally did this to make it difficult for my friend to pursue the case so she can't do anything as the NBI required all of this but apparently the relatives are doing this for revenge. She file a complaint against the relatives with some local authority and it will eventually be taken up to court within the next couple of weeks. I really think this people deserved punishment as they are also falling for extortion and endangering my friend's children's life.

A criminal offense that involves INTERFERENCE, through words or ACTIONS, with the proper operations of a court or officers of the court.

PD 1829: Penalizing Acts that Constitute Obstruction of Justice
 
The general meaning of “obstruction of justice” denotes an INTERFERENCE with the orderly administration of law, IMPEDING or OBSTRUCTING THOSE WHO SEEK JUSTICE in court or those who have duties or power of administering justice therein.  PD 1829 penalizes any PERSON WHO KNOWINGLY or WILLFULLY OBSTRUCTS, impedes, frustrates or DELAYS the apprehension of suspects and the INVESTIGATION and prosecution of criminal cases by COMMITTING any of the following nine acts.  These acts will be discussed separately on enumeration.  Note that if any of the foregoing acts is committed by a public official or employee, he shall in addition to the penalties provided thereunder, suffer perpetual disqualification from holding public office.

Hello Attorney, could you possibly help us and let us know how many months waiting period is allowed to file the case after the local zone authority papers has been issued? Does it needs to be filed ASAP or it can wait for couple of weeks or so? Also, how much to file 4 or 5 different cases like obstruction of justice, extortion, libel and slander with perjury and two more. Can it be filed all together? We need to know as my friend may need to go home and confront this nasty idiots! Thank you so much!