Updated

Police on Thursday were preparing to charge the son of Papua New Guinea's acting prime minister with murder after the body of a 29-year-old waitress was found at the family home.

Theo Abal, 21, will likely make his first court appearance Friday once he is charged in the killing of the woman, police spokesman Dominic Kakas said. He could face the death penalty if convicted.

A guard at the house told police he saw Abal and the woman arrive home in the early hours of Monday and head for a garden on the premises. Police said that the guard later heard the woman scream and that Abal confessed to killing her.

Kakas said her throat had been cut. A kitchen knife found near her body was the suspected weapon, he said.

Acting Prime Minister Sam Abal said he personally reported the "alleged murder" to Police Commissioner Tony Wagambie on Monday after the woman's body was found at his home in the capital, Port Moresby.

He made no comment on his son's alleged confession but pledged to cooperate fully. He said in a statement Tuesday that if any of his relatives are involved, "they will face the full brunt of the law and will not be treated differently from anyone else."

Theo Abal was arrested at a Port Moresby hotel Tuesday night and was still in police custody Thursday.

Kakas said police expected to charge Theo Abal with willful murder but were waiting for relatives to identify the woman's body before filing, and Kakas said that could delay the process. Abal still had not been charged Thursday afternoon.

Kakas said the island nation has had the death penalty for only a few years and has yet to carry out an execution, though a handful of defendants have been sentenced to death.

Theo Abal, the younger of Sam Abal's two children, is unemployed and lives at his father's house.

Kakas said the dead woman worked as a waitress at a Port Moresby hotel. Her name has not been made public.

Wagambie said Tuesday that the acting prime minister was away from the house and was alerted to the death by the security guard, who found the woman's body in a banana garden.

The guard alleged that he opened a gate for Theo Abal and the woman shortly before dawn Monday and that the pair walked hand in hand into the garden, Wagambie said.

"The guard claims that some 20 minutes later, he heard the woman scream, and further claims that some time after, Theo comes out and tells him that he had killed the woman and left her body in the banana garden," Wagambie wrote in his statement.

Sam Abal is standing in for Prime Minister Michael Somare, who stepped down in December because of ill health and to clear his name before a tribunal that is investigating allegations that he failed to disclose his full income.