Police have admitted the Christchurch mosque gunman could have been planning his attack weeks before March 15.
An Official Information Act request by Newshub reveals the shooter flew a drone over the Deans Ave mosque on January 8 - 10 weeks before he would open fire and kill 51 people.
He launched it out of Hagley Park, just across the road in an evil act of premeditation.
The news has sickened young Kiwi Muslim leader Haris Murtaza.
"They were being scoped out by the gunman, and he was doing his research," Murtaza told Newshub.
The drone is another factor in a Newshub investigation that has uncovered extensive planning by Brenton Tarrant.
Imam Gamal Fouda is convinced Tarrant even prayed at the mosque in the lead-up.
"If you look at the way he behaved in here. He knew the place like his house," Fouda told Newshub.
The police murder investigation found evidence that Tarrant had parked across the road from the mosque, so Newshub requested more detail under the Official Information Act. The response could not confirm if Tarrant had parked opposite - but it did confirm he performed a flyover.
"However, on 8 January 2019 a drone used by Mr Tarrant took flight over the Deans Ave Mosque," police confirmed.
"The start and endpoints for the drone usage was in Hagley Park across from the mosque."
Murtaza said the news is painful.
"To go scope out what the area was like, and what the mosque looked like, the entrance points and the parking everything like that and basically get a blueprint - it really concerns me - but also hurts."
Murtaza is part of a group of young Muslims that have prepared an investigation into the attack for the Royal Commission.
He said police should have been prepared.
"It should have definitely been on the radar for the police".
He said the use of the drone is a missed warning by police and New Zealand intelligence.
Murtaza said it fits a pattern of missed warnings - alongside Tarrant's visits to Al Noor Mosque, purchase of guns, travel to unusual destinations such as Pakistan, Afghanistan, and North Korea and his online extremism.
Murtaza blames New Zealand officials for not realising the country had a problem with white supremacy, which the Muslim community knew was on the rise.
"It just paints the picture that police were completely oblivious to any of this going on," he said.
"They were not focussing on this at all and did not have a clue."
The mosque was on the gunman's radar - yet he was not being tracked at all.