"I did not want to put myself in the unit that night because I knew something was going to happen," David Ronald Morgan told Launceston detectives during an interview.

"Whatever happened I would have been physically seen inside that unit and there was no way I was going in it."

On Thursday, Launceston jurors in the Supreme Court trial of Mr Morgan, 57, finished watching a series of videotaped interviews he had with police, some at his own request.

The South Australian man has pleaded not guilty to the murders of Angela Maree Hallam, 31, and Joshua Eric Newman, 21, on the night of August 15, 2012.

Both the Crown and defence agree it was Marco Daniel Rusterholz who physically stabbed to death and set alight the couple's bodies in a unit in Pioneer Parade, Ravenswood.

During an interview with police on September 18, 2012, Mr Morgan recalled several associates talking at McDonald's in Burnie on the day of the murders.

He said there was talk about Ms Hallam owing Mathew Coventry many thousands of dollars and Rusterholz suggested she had to be "fixed up ... shortly."

Mr Morgan told police he believed Ms Hallam would be very badly assaulted.

In his last interview on September 19, 2012, Mr Morgan revealed that Rusterholz had asked him to check if Ms Hallam was at home - hours before the killings.

The accused said he dropped blankets outside the front of Ms Hallam's unit, called her to tell her he had done so, declined her invitation to come inside and rang Rusterholz to tell him she was at home with people.

Crown prosecutor John Ransom closed the state's case.

Justice David Porter told jurors to return on Monday at 10am.