Scientists still working to make 9/11 DNA matches 24 years later

NEW YORK -- On the morning of September 11th , 2001, Mark Desire rushed down the World Trade Center just after the first plane struck the north tower.

"The rumbling, it was the loudest, most violent time of my life," said Desire. "That was a defining moment for me."

It was his job to collect evidence for the New York City Medical Examiner's office.

"That morning, it was all hands on deck, and our job was to preserve the evidence, so that means the victims, potential weapons, and pieces of the plane," he said.

He was standing close to the south tower when it collapsed.

"I was running and thinking I'm going to make it through the door and then I got hit and I went through the window," he said.

Desire jumped partially inside a nearby building; the debris crushed his foot.

"I would a