They grew louder and more frequent. Soon I could see the police's Eagle helicopter hovering in the distance - but this is not an unusual sight in Auckland.
At first the reports were scattered and unconfirmed. Someone was seenwith a knife or gun at a supermarket.
But more accurate witness reports started coming in fast and video was being posted online of the incident. People filmed themselves fleeing the mall, scared and in panic.
He was the man I had spent the past four years investigating and someone I sat just metres away from in a courtroom many times. He was a person I knew was not only capable but wanted to carry out such a horrific attack.
It was what he had planned and what those who knew him had long feared - public, unsophisticated, and indiscriminately targeting everyday New Zealanders.
I messaged my colleague Jared Savage, who I had worked with during S' cases.
"I hope this mass stabbing/shooting in LynnMall isn't Mr S … he's out that way," I said.
We both had the same horrible feeling yesterday. We also both knew the man, known only as S for legal reasons, was serving a 12-month supervision sentence in the area for possessing objectionable Islamic State material and failing to comply with a police search.
Just weeks earlier, on August 16, the Herald had published a front-page report about his case, his criminal history, and how the Crown unsuccessfully attempted to charge him under the Terrorism Suppression Act 2002 last year.
By now we had learned the attacker had been shot and killed by police, but not by a brave constable in the right place at the right time. We were informed of "undercover cops" who were armed and quickly converged on the supermarket as though they were already there.
What person would be followed by a team of armed police to the supermarket?
While ringing my police and government sources, armed officers were also converging on a nearby location of interest.
But it was what my sources didn't say that confirmed my suspicions. When bluntly asked if S was the assailant there was more often than not a silent pause on the call.
"I can't say," one source told me. "But it's a national security matter because of who it is. It's terrorism. The Prime Minister and Commissioner are being briefed."
The fear of such an attack was exactly why authorities had desperately tried to keep S in custody for as long as possible and had succeeded in doing so for three years before the legal options ran out.
It was why even after being released into the community he was under 24-hour surveillance from a covert elite police task force, the Special Tactics Group.
Throughout his court cases the lawyers, police, court staff and journalists all spoke to me of how we shared a terrible nagging thought that S was simply a ticking bomb.
It felt like there was nothing anyone could do to stop him or help S quash those extremist beliefs in his mind. It felt like the best outcome would be limiting the damage he could inflict on others.
I had watched him throughout his trial this year as he displayed a combative attitude towards authority, frequently directly outbursts at lawyers and the judge.
He said the Crown had wasted years of his life.
"I thank God, there have been prophets, other prophets who have been to prison," he told the courtroom.
"It's just like a test … You guys put me in prison cause I'm a Muslim and you don't like my religion, that makes you an enemy. Allah says you will be punished."
He was highly paranoid, and dismissed his charges as fake. We knew one day soon he would be back in the community.
At his sentencing in July, the court heard S had been assessed as being a high risk of reoffending. But one comment from a pre-sentence report read aloud by the judge made even more hardened courtroom lawyers and reporters widen their eyes.
"S had the means and motivation to commit violence in the community."