MANILA - The complaint filed before the International Criminal Court (ICC) against President Rodrigo Duterte and other top Philippine officials may take as long as 10 years before it reaches the trial stage.

This is according to a Filipina lawyer who worked at the Office of the Public Counsel for the Defense of the ICC at The Hague and is currently a legal consultant for the Commission on Human Rights (CHR).

• Read: Crimes against humanity complaint vs Duterte

"We shouldn't look at the ICC the same way we look at the Philippine legal process because they're different. As an international court, it operates within the international environment where foreign affairs and diplomacy come in," Atty. Jenny Jean Domino told ANC on Tuesday.

Atty. Domino explained that the "complaint" filed by the lawyers of self-confessed hitman Edgar Matobato is currently with the Office of the Prosecutor (OTP), which considers the affidavit a "submission of information."

She said the OTP needs to evaluate first the seriousness of the submission of information before it can do a preliminary examination, which is required before proceeding to a full-blown investigation.

• Read: Why Duterte, top PH officials were accused before ICC

The OTP will only be deciding on the reasonable basis during the preliminary examination stage. It will then go to the ICC's pre-trial chamber to ask authorization for a full-blown investigation.

The ICC may only send representatives to the Philippines at this stage. The court may also issue a warrant of arrest or summons if necessary during a full-blown investigation.

"The timeline in the ICC record starts from the time the OTP publicly announces a preliminary examination is being conducted in a particular country... From this time until trial, again, the cases vary. It can take as long as 5 to 10 years," she said.

Atty. Domino said the timeline depends on the quality of the complaint -- the evidence -- filed by the prosecution, where the usual criminal law principle applies.

WHAT IF THE STATE REFUSES TO COOPERATE?

Non-cooperation by a state may pose difficulties for the ICC, especially during a full-blown investigation, said Atty. Domino.

She explained that representatives from the ICC would still have to go through the processes of the concerned state when they conduct their probe, which will require state cooperation.

"The investigating group will still have to go through the local process. It will require state cooperation," she said.

Asked what the ICC can do if the state refuses to cooperate with the investigating team, the lawyer said the international court may refer the case to the Assembly of States Parties to the Rome Statute.

"If it is in the preliminary phase, it might be hard to get relevant information that could be used as evidence later on. But if there's already a full-blown investigation, the ICC may refer the matter to the Assembly of State Parties," she explained.

"It may present difficulties. But actually, 'yun nga e, again, that's a matter of foreign affairs because as an international court, it has to deal with different states. There are ways," she added.

The Philippines ratified the Rome Statute on August 30, 2011 but its date of effectivity starts on November 1, 2011.

Atty. Domino said that even if the Philippines decides to withdraw from the Rome Statute, it will not affect the exercise of jurisdiction of the ICC.

The complaint filed by Matobato's camp claims Duterte violated the Rome Statute due to his alleged involvement in extrajudicial killings when he was mayor of Davao City and now as Philippine President.

• Read: Duterte on ICC: Let it be

But Atty. Domino said the camp of Matobato might find it hard to prove the link between the two because of the difference in time-frame and context.

"The connection might be to tenuous. I'm thinking about the evidence -- how do you link these before the court. How do you prove the liability, one as mayor, one as president," she said.