Tickets are on sale now to hear Marine Corps veteran and author Mark “Oz” Geist recount his experiences in the Benghazi siege in 2012 at the University of Colorado Colorado Springs.

Geist is expected to speak about “his life and leadership lessons,” organizers said, from 6 to 8 p.m. on Oct. 9, in the Shockley-Zalabak Theater at the Ent Center for the Arts.

Tickets are $12 for adults and $7 for students and are available online by clicking here.

Geist co-authored the book “13 Hours: The Inside Account of What Really Happened in Benghazi,” the basis of the movie “13 Hours: The Secret Soldiers of Benghazi.”

The accuracy of Geist’s account has been challenged after the movie came out in 2016, particularly the key contention that the security team defied a stand-down order to save lives. Then a law enforcement officer from Colorado Springs, Geist campaigned for Donald Trump in Colorado and was a speaker at the 2016 Republican National Convention.

Geist was a member of the security team at the diplomatic outpost in Libya. The team was credited with helping save more than two dozen lives during the firefight that killed four Americans, including Ambassador Christopher Stevens.

Chance Hill, a University of Colorado regent for the El Paso County district, notified his supporters about the event via email.

Hill, a former CIA officer, said the UCCS event was Geist’s first address on a college campus.