I had the Lindt Cafe siege gunman in my sights and my finger on the trigger – but I never took the shot. Now I’m haunted by the horror that unfolded…

A former police sniper hunted for the Lindt Café siege nearly a decade ago is still wracked with guilt for failing to fire when he had a clear shot at the gunman.

Mark Davidson was the senior sniper involved in the Sydney Lindt cafe siege on December 15, 2014, when Man Haron Monis stormed the CBD armed with a rifle and claiming he had a bomb.

The officer, codenamed Sierra Three 1, was stationed opposite at the Westpac building on Martin Place during the 16-hour standoff.

Of the 18 hostages in the cafe, Manis shot and killed Tori Johnson, 34, and Katrina Dawson, 38, was killed by police bullet fragments.

Davidson told 2GB presenter Ben Fordham on Tuesday that he still feels overcome with guilt for not shooting Monis at the beginning of the siege and preventing the couple’s deaths.

Davidson explained that he, along with two other snipers, had a clear shot at Monis at 7:30 pm, almost seven hours before police stormed the cafe.

“At the beginning of the getaway, he (Monis) showed himself in front of the windows and doors… I was able to see him for about 10 minutes around 7:30 p.m.,” Davidson said.

‘I felt guilty for not shooting when he could clearly and easily be shot without anyone else getting hurt.

‘I guess I feel guilty for not killing someone, it was something you could achieve and then potentially save everyone.

“We had 10 minutes to prepare the best possible shot… and we could have ended the siege at 7:30 pm and not at 2 am, when Tori Johnson and Katrina Dawson died.”

Davidson said he feared Monis was holding a “dead man’s switch,” which would have detonated a bomb if the person holding it died or dropped the device.

“We couldn’t really determine if he had one of those,” Davidson said.

‘I chose, we chose, not to shoot him at that time when we could see him at 7:30 p.m. “We made that decision and we have to live with it.”

However, Davidson said police chiefs changed the game plan for dealing with the hostage situation, after years of rehearsing one response only to have another implemented at the last minute.

‘YO“It’s a bit like a rugby league team practicing the move prepared for a grand final and practicing it all year and then getting to the grand final,” Davidson said.

Then the captain said “we are not going to do the fixed movement that we have practiced all year. We are going to do something new.”

‘They have changed the goal at the last moment, when it matters most. We had the capacity to do the work that needed to be done.

“It was just the next level in management that didn’t allow that to happen.”

NSW Police have previously rejected Davidson’s claims that he had a good chance to shoot the terrorist and could have saved the lives of the hostages.

Police said Davidson’s rifle would not have penetrated the window glass of the Westpac building or the window glass of the Lindt Café.

“Breaking the glass of Westpac, i.e. creating a hole, and then shooting through it would have taken a long time and would have created a noise that Monis could have heard,” police said.

However, Davidson refuted the claims and explained that he and his team had enough time to make a hole in the window glass to clearly shoot Monis.

Police have rejected claims by a Lindt cafe siege sniper that a hostage’s life could have been saved if he had been allowed to shoot.

Davidson said the Lindt Café siege was the “last straw” in a series of traumatic events that led to his medical discharge in 2017 after nearly 25 years on the force.

The former sniper suffers from post-traumatic stress disorder, often has flashbacks of Tori Johnson’s murder, and has a worrying neurological problem that causes his arm to shake.

He explained the guilt he felt over the Lindt Cafe siege and his post-traumatic stress disorder inspired him to create his podcast ‘The Lawyer, the Sniper and the NSW Police’.

“(Guilt) was something I harbored initially and worked through that process,” Davidson said.

‘The podcast was a good thing that came from me. “It inspired me to do something positive, to speak out and try to fix things so that the same mistakes that occurred in the Lindt Cade siege do not happen again.”

Davidson will appear on the Guilt episode of SBS Insights on Tuesday at 8.30pm