Maureen Miller
AC360° Writer

We're learning new, exclusive details on the massacre at Fort Hood.

Tonight, you'll hear from Sgt. Mark Todd, an Army civilian police officer who along with his partner, Sgt. Kimberly Munley, shot the alleged gunman – Maj. Nidal Malik Hasan.

Maj. Hasan, an Army medic survived his gunshot wounds. But 12 of his alleged victims died.

Sgt. Todd will tell you what happened at Fort Hood's Soldier Readiness Center yesterday when Maj. Hasan allegedly opened fire.

We also heard today from neighbors of Maj. Hasan, who said he cleanned out his apartment the morning of the shootings.  Several neighbors said he gave them copies of the Quran.

The neighbors thought Maj. Hasan was moving out because the Army was shipping him overseas for war duty.

We also talked with a former classmate of Maj. Hasan's at the Uniformed Services University of the Health Sciences in Bethesda, Maryland. He said they took an environmental health class together. The former classmate said Hasan wrote about his opposition to the war on terror, while other students in class focused on such topics as mold in homes and dry cleaning.

We're keeping them honest. Tonight, we'll look at how Hasan's alleged hate for the war on terror may have gone unnoticed by some Army officials. After all, according to reports, Hasan was promoted to the rank of Major in May. Though, investigators said Hasan received a poor performance review at Walter Reed Medical Center and was transferred to Fort Hood.

Join us for this story and much more starting at 10 p.m. ET.