Gunman Man Haron Monis sat inside the Lindt café in Sydney's Martin Place and sipped coffee for at least an hour before deciding on the exact time to seize control of the inner city venue, according to reports.

Security footage from the Seven Network's Martin Place studio, and being reviewed by police, also shows Monis strolling up and down the pedestrian mall, wearing a backpack, about 8.30am on Monday — just over an hour before the siege began.

Police are trying to piece together the self-styled cleric's movements before he locked the door on the inner city café and pulled a sawn-off shotgun from his blue bag, setting of a deadly, 16-hour siege.

News Corp reports that as Monis waited inside the café on Monday morning, he had a chance encounter with one of his lawyers.

"He called my name out and said, 'How are you going?'" said the lawyer, whose name was not published from fears he could be exposed to threats.

"I didn't recognise him at first so I walked over to him."

The lawyer said Monis invited him to sit down and join him for a coffee but the lawyer declined, saying he had to be in court.

The two spent several minutes talking about one of the many legal matters Monis was facing.

"He was cool as a cucumber, not agitated, not scoping the place out, not looking over his shoulder," the lawyer said.

When Monis seized control of the café, he told his hostages his backpack was filled with explosives and snipers could see wires poking out of it, which was one of the reasons they decided not to take a shot at him. But when police later examined the backpack they discovered only an old stereo speaker inside.

The NSW State Coroner has now released the bodies of Monis's victims, Tori Johnson and Katrina Dawson, back to their families for burial after completing post-mortems into their deaths.

© ninemsn 2014