MANILA, Philippines—Energy Undersecretary Datu Zamzamin L. Ampatuan has appealed to the public to respect the due process of the law as Andal Ampatuan Jr. has voluntarily submitted himself to the government.

"This is the most important thing that happened today—that Ampatuan Jr. had submitted himself to a voluntary investigation," the Energy official said via phone.

His second cousin, Ampatuan Jr., has already submitted himself to presidential adviser Jesus Dureza in General Santos City Thursday.

"From the understanding of the Ampatuan family, this (submission) is voluntary, just to clarify the allegations on (Ampatuan Jr.'s) participation. We're still not sure, not clear on what the Department of Justice will do. The lawyers are already discussing how they're going to handle this situation," Zamzamin Ampatuan explained.

The energy official said he could not provide more details.

"The most important thing is that justice should be pursued, and whoever the culprit is, should be pinpointed. Credible investigation should be pursued so a clear direction could be achieved. This is a call for justice," Ampatuan stressed.