Two plainclothes detectives, who had no bulletproof vests and "with little regard for their own safety," were hailed on Wednesday as heroes after authorities revealed that they were the ones who stopped Christopher Harper-Mercer from killing more students at Umpqua Community College in Roseburg, Oregon, last week.

At a news conference, Douglas County District Attorney Rick Wesenberg revealed new details on the school rampage that led to the death of 10 people on Oct. 1, pointing out that Harper-Mercer was wounded by gunfire from the two responding lawmen before he decided to kill himself, the Los Angeles Times reported.

Wesenberg also pointed out that aside from the nine people Harper-Mercer killed—eight of his classmates and his professor—he also wounded nine other students.

Wesenberg said the gunman could have killed more students were if not for the quick response of the two detectives, adding that their use of force was justified.

"I want everyone to know of the selfless act these officers made in responding to the scene," the district attorney said. "They had little regard for their own personal safety and they saved many, many lives that day by their heroic acts."

Earlier reports made no mention of Harper-Mercer getting wounded by police gunfire before he took his own life.

Authorities identified the two detectives as Joe Kaney, 49, and Todd Spingath, 41. Wesenberg said the two lawmen rushed to the scene after a call for help and immediately saw Harper-Mercer in a doorway inside Snyder Hall after he began shooting fellow students and their professor inside their English class.

The district attorney said Harper-Mercer saw the two detectives approaching with drawn guns and fired at them. They returned fire, with one bullet piercing the right side of the gunman's body, Wesenberg said.

It was at that point that Harper-Mercer decided to point his gun at himself and pull the trigger.

Officials found six firearms in Harper-Mercer's possession inside the school. He wore a flak vest and had at least five more extra magazines of ammunition left. Eight other weapons were recovered at his home.