The officer who shot dead terrorist Man Monis to end the Sydney Lindt Cafe siege has finally been unmasked as he recalled how the worst moment in the aftermath when he learned the hostage who died in his arms was killed by a police bullet.

Ben Besant, whose identity was suppressed for almost 10 years, told Channel Seven‘s Spotlight that his world came crashing down when then NSW Assistant Commissioner told officers that a round of bullets fired ricocheted off and killed lawyer and mother-of-three Katrina Dawson, 38.

Mr Besant, who watched Ms Dawson die in his arms only hours earlier after leading the elite NSW Police Tactical Operations Unit (TOU) into the cafe on December 16, 2014, said the news shattered him.   

‘When I heard this I remember I felt like vomiting,’ he told reporter Chris Reason on Sunday night’s program.

‘I was just completely overwhelmed, like my world just closed in around me.’

After that Mr Besant said he started seeing Ms Dawson, who was killed by a ricochet, ‘everywhere’, particularly if a woman had the same hair colour.

‘Every time I saw a blonde lady, I’d just completely saw it as her,’ Mr Besant said.

‘I’d have a panic attack in that moment.’

The then undiagnosed Post Traumatic Stress Disorder (PTSD) was so bad that Mr Besant  would walk around the police centre with his hand on his gun at all times. 

‘I was ready for the next fight, next threat,’ Mr Besant said

‘I’d even picture other police officers as I walked around just being shot, not shooting at me or me shooting them.

‘I just saw them being shot and bleeding out in front of me. I was in a dark place there for quite a long time.’

Mr Besant revealed when he and his Alpha team of TOU officers stood around the corner waiting for the order to storm the cafe, they believed Monis had a bomb in a large backpack he was wearing, which later turned out to be a ruse.

When three hostages escaped from the cafe prompting to Monis to fire a shot, which missed the fleeing trio, Mr Besant expected to hear the order to storm in. 

‘I completely believed going in would mean my death,’ Mr Besant said.  

‘We joked about this was the last last job we’re going to do and how we’re all gonna get blown up …. but, and then it got real and we all went quiet.

‘That’s when we started text messaging our partners and getting certain photos of our kids and saying our goodbyes.’

Then pregnant with their second child, Mr Besant’s wife Lisa switched on the television to follow the terrifying drama unfold, which happened directly across from Seven’s Sydney studios in Martin Place.

The couple’s toddler made a startling observation about the officers, whose faces were almost completely hidden behind their helmets.

The little girl was able to recognise Mr Besant from his blue eyes- the only facial feature that was visible.

‘She said ‘look, there’s daddy’,’ Lisa said.

Lisa then received a farewell message from Mr Besant with a request of a picture of their daughter.

‘I wasn’t quite sure he’d meet our other child … that wasn’t good to think that,’ Lisa said.

Despite Alpha group tensing for the order to go in, it did not come until after 2am the next morning after three other groups of hostages had made a run for it and Monis had executed cafe manager Tori Johnson with his shorn-off pump action shotgun.

It was only then when officers finally stormed the building, 16-and-a-half hours after the siege started. 

Mr Besant, who led the charge along with an officer holding a bullet shield, said he looked across the cafe straight at Monis and focused the torch light mounted on his gun and laser site on the terrorist. 

‘I remember seeing his shotgun pointing straight at us,’ Mr Besant said.

 ‘We were looking straight into each other’s eyes.’

Mr Besant said as in the movies time slowed down ‘so much’ at the crucial moment.

‘I knew the only way to potentially save anyone else in that cafe was for me to kill him,’ Mr Besant said.

‘I remember looking him in the eyes and I remember thinking ‘I’m gonna kill you’.’ 

‘I believe I got one or two shots off at the start. And then, yeah, the huge muzzle flash (as Monis fired back).

‘I remember just flinching and just waiting for it to impact on me, but it didn’t.’

He kept moving towards Monis and firing. 

‘I was completely fixated on shooting him,’ Mr Besant said

‘He’s still not down. And I know I was hitting him, my laser pointers on him and he still hasn’t gone down.

‘So that’s when I raised up my laser pointer up his neck and started firing at, at his head. I needed to get him down. I needed to stop him detonating the bomb.’

Finally the shooting stopped. 

‘I remember standing with my gun looking down at him and oh yeah, I became acutely aware that he was no longer a threat,’ Mr Besant said

‘The sinking in of me standing over this man that I just violently shot and killed.’

However, there was something even more traumatic to come as police cleared out the six remaining hostages.   

Mr Besant said as he searched the space he looked underneath some tables.

‘I can see that the top of what I believe is someone’s head,’ he said.

‘  realised it was, it was a blonde-haired lady in like a business suit, ends with a ponytail.’

The next moments as he cradled Ms Dawson, a Sydney barrister, in his arms are something Mr Besant said he sees ‘daily’

‘I was just looking into her eyes,’ he said.

‘Each breath she was taking was, was less and less.

‘I knew in this moment that I couldn’t do anything. 

‘I desperately wanted, I was just willing her to take, to take another breath.’

‘Within myself, I’m like, ‘please, please just take another breath, please’.

‘Each breath got shorter and, shorter and shorter and then she stopped breathing.

‘Something I will never forget, she literally died in my arms. The saddest moment of my life.’ 

A coronial inquiry into the siege in 2015-16 was scathing about the police response to the siege, particularly waiting so long to send in the TOU assault team.

Throughout those proceedings, Mr Besant’s name was suppressed and he was given the label ‘officer A’. 

It took a nine-year NSW Supreme Court battle backed by Seven for Mr Besant to be finally able to reveal his identity.

The near decade suppression impacted Mr Besant’s PTSD and he claimed it cost him his career and his marriage to Lisa.

‘It’s become such a big issue for me to be able to get my name back,’ he said.

After the PTSD became too overwhelming to stay in the police force, Mr Besant found a second career as a carpenter.