During a six-month investigation, CBS News interviewed dozens of sources and reviewed hundreds of pages of Defense Department and Air Force Academy documents. CBS News spoke with more than a dozen cadets, and four of them agreed to speak on camera to share their stories with Norah O'Donnell.

Two cadets who are currently enrolled at the Academy talk with O'Donnell in silhouette because they fear risking their careers by going public. Two former cadets, who left the Academy in 2013 -- after being sexually assaulted -- share their stories for the first time in an on-camera interview.

These cadets' accounts and the results of the investigation led by investigative producer Jennifer Janisch begin airing Monday, Dec. 11, on "CBS This Morning."

A preview aired Sunday night on "CBS Evening News." O'Donnell spoke with one cadet named Emily Hazen who described her encounter.

"I was sexually assaulted my freshman year and I did an administrative turn back for a semester and the sexual harassment I endured eventually made me leave," Hazen said. "My perpetrator would follow me on runs. He would ... tell me he urinated on my car. He would write crude things on my car, like, in the fog. He would send me horrible text messages. He would stalk me, he would ask me where I was going in my little brown dress."

O'Donnell asked if this man was ever reprimanded in any way?

"He was talked to by his commander about a very crude text message I received and told that that was unbecoming of an officer," Hazen said.

That cadet ended up graduating; Hazen left the Academy.

Emily Hazen (L) and Melissa Hildremyr (R) speak with "CBS This Morning" co-host Norah O'Donnell. CBS News

Tuesday's "CBS This Morning" will feature the first television interview with Teresa Beasley, who worked for a decade as the Air Force Academy's top official on sexual assault prevention and response. Beasley tells O'Donnell she has serious concerns about how the Academy accounts for sexual assaults and says commanders are not supportive of those who file complaints.

Beasley also reveals -- and CBS News confirms -- previously undisclosed details about two violent attacks on cadets that occurred on a public trail behind the Air Force Academy in Dec. 2014 and Jan. 2015.

Also Tuesday, the Air Force Academy's Superintendent, Lt. Gen. Jay Silveria is scheduled to join "CBS This Morning" live in-studio.

Watch Norah O'Donnell's investigative reports on sexual assaults at the Air Force Academy beginning Monday, Dec. 11 on "CBS This Morning" at 7 a.m. ET/PT.