MANILA, Philippines –Justice Minister Leila de Lima on Monday (February 11th) ordered government investigators to look into the mysterious prison death of a key witness in the murder of a prominent environmentalist, AFP reported.

De Lima gave the order after an autopsy indicated that the witness, Dennis Aranas, did not commit suicide as jail officials had said, but may have been murdered.

"I ordered the NBI (the official National Bureau of Investigation) to probe it," she said in an SMS message to reporters.

Aranas was a key government witness to the January 2011 shooting death of journalist and environmental activist Gerry Ortega. The state alleges Joel Reyes, former governor of the island province of Palawan, and his brother Mario plotted the murder. Joel Reyes is believed to have fled abroad.

Aranas, who allegedly acted as a look-out in the murder, was in jail when he died with jail officials telling his family that he had hanged himself.

"He was killed while horizontal or lying down. He was held down by four or five assailants," Public Attorney's Office head Persida Acosta told AFP, quoting the office's forensic expert.