"The photographs were an afterthought."
When NYPD Aviation unit Detective Gregory Semendinger took to the air in his Bell Jet Ranger helicopter on Sept. 11, 2001, his goal was to help save lives.
"We looked for people on the observation deck of the South Tower," Semendinger recalled to NBCNewYork Thursday in his Wantagh, Long Island home. "But the smoke was too thick. We never saw anyone."
As his chopper circled the devastation below, the photography buff grabbed his camera and captured history- more than 240 chilling photos of the worst terrorist attack in U.S. history.
It wasn't easy to watch.
While in the air, Semendinger and his partner caught a glimpse of the second plane crashing into the South tower; then, watched in horror as both towers collapsed.
"There was no noise, no sound, no vibration," Semendinger said, his hands clasped tightly in his lap. "It's still hard to think of all the people who were there. They had so little chance."
Most of Semendinger's photos have never been made public until now. The federal government released a number this week after of Freedom of Information request from ABC News.
"It's a totally different perspective of the whole incident," said the now retired thirty five year veteran of the NYPD.
"It gave the total picture. I was fortunate to be there to see it."
Ironically, Semendinger had flown over and photographed the World Trade Center during quieter days and had even rescued a pregnant woman from a roof of the Twin Towers after the 1993 terrorist attack.
That he couldn't facilitate another rescue eight years later is his everlasting regret.
"We were there minutes after it happened. It's just unfortunate no one made it to the roof."