Mr Challis left his home at Rushcutters Bay at 3:30am to drive to the Fuller's Bridge area. He arrived at around 4:00am, and parked his car on the dirt track just off Millwood Avenue. This was the same track on which the bodies of Bogle and Chandler were later found.

Mr Challis left his car, a white Ford Escort, and began walking along the track towards the Chatswood Golf Course. It was not quite light, and he heard a car coming along behind him. He hid, not wanting to be seen. The car was a Holden station wagon, which stopped and parked in the turning area at the end of the track.

Another track ran parallel to the first, but higher up, and Mr Challis returned to his car along this track. At 4:30am he left his car again, this time crossing Millwood Avenue and heading north along Lady Game Drive.

As he walked, a car pulled up parallel to the direction in which he was walking, and stopped, half off the road. It was a Ford Prefect. In the light it seemed to be dark brown in colour. He looked directly at the driver, and the driver in turn looked directly at him. The driver looked pale. Challis thought that the driver was going to speak, but he didn't. There was a woman in the car, obscured by the driver. Having later seen pictures of Dr Gilbert Bogle, Mr Challis said that he believed that Bogle was the driver.

Mr Challis continued walking the 800 metres along Lady Game Drive to the Grosvenor Road turn off. There he spoke to another man. This man asked him about a 5 year old child, a boy who was walking on Lady Game Drive. The man asked Challis if the boy was with him. Challis told the man that the boy had nothing to do with him, and then walked away because it was no concern of his.

Walking back towards his car, he saw that the Ford Prefect was now parked in a different position. Mr Challis returned to his own car after 5:00am.

Mr Challis had no left hand, and hence it would be difficult for him to reverse his car from the track back onto Millwood Avenue. Instead he decided to drive to the end of the track and come back.

As he drove past the spot where Bogle's body was later found, Mr Challis did not notice anything. However, in the circumstances he was unlikely to. He reached the other end of the track, and turned the car around. There was no sign of the car which had passed him earlier

He was returning back along the track at about 16km/h when a man crossed the track in front of his car. At this stage he was some 18 to 27 metres from the spot where Bogle's body was found. The man crossed the track between 2 and 3 metres in front of Challis' car, and then slid down the bank towards the river.

Challis' description of this man apparently varied. The man was about 40, 170cm tall, either well-built or with a medium build, and with broad shoulders. He had blond hair which was long at the back. He wore a dark t-shirt, and either trousers, or brown shorts and sandals.

Mr Challis thought little of this incident, and continued along the track until he arrived back at the road. Across the intersection, he saw some people throwing each other into the river and generally mucking about. Mr Challis then left the area.