AN Indonesian security guard has said that he heard screaming coming from the scene where a Bali policeman was killed, just before he saw a Byron Bay mother grabbing a man.

AAP reported that the security guard saw Sara Connor grabbing a man on Kuta Beach, but walked away from the alleged murder scene, believing they were just "joking around", a court has heard.

The security guard, named by national media as Suryana, was working the night shift at Pullman Hotel when he allegedly heard the screams about 1.05am on August 17, the night policeman Wayan Sudarsa was later found dead and bloodied on the beach.

"I heard loud and long screaming ... Aaaahhhhh ... from Kuta Beach," Suryana told Denpasar Court on Tuesday.

He stopped at the entrance to the beach and saw a man lying face-up on the sand, and to his left, Ms Connor, AAP reported.

"(Her) left arm looked like it was grabbing ... locking the victim's neck."

Meanwhile, Mr Suryana said a "western male with long hair was sitting on the victim's belly".

"Both of his hands were holding the victim's hands ... the victim was motionless."

Mr Suryana told the court that he was about four to five metres away from the three people, but walked away thinking they were just "joking around".

It was not until about 4.30am that police approached the Pullman Hotel security guard and told him about Mr Sudarsa's death.

"I saw (Mr Sudarsa) lying (on the sand). He was still in his uniform, only (his shirt) was unbuttoned. He was without his left shoe and his left leg was scratched.

"His face was covered with blood and sand."

Ms Connor has denied the accusations.

"I never lay in the position next to the body. I never tried to grab (Mr Sudarsa's) neck," the 46-year-old said.

Speaking after the hearing Ms Connor told reporters she had "faith" the judges would understand she was "innocent".

MsConnor and her British boyfriend David Taylor face charges of murder, fatal assault in company and assault causing death, with prosecutors alleging they attacked Mr Sudarsa on Kuta Beach on the night of August 16 and left his lifeless body in the sand.

Ms Connor continues to declare her innocence, saying she did nothing but try to separate the pair.

Mr Taylor is expected to appear in court while Mr Connor is due to return next week.