In an heart-wrenching interview with the Long Island family of 21-year-old Marine Greg Buckley Jr., the father revealed his son knew of an insider attack on the Afghanistan base that ultimately killed him.

""He told me, if I have to stay here until November... I'm not going to come home," Greg Buckley Sr. told CNN in an interview broadcast on Sunday.

When the father said he didn't understand, the Marine allegedly said, "You've got to be able to tell mom and Justin and Shane that I'm, you know, going to be killed over here."

When the father asked if it was out in the field, Buckley Jr. said, "No, in our base."

Buckley Jr. was stationed in Garmsir, in Afghanistan's Helmand Province when he was killed last month by an Afghan police officer he was training in anticipation of the U.S. withdrawal from Afghanistan in 2014. The two had reportedly shared a meal just before Buckley Jr. was killed.

Watch the video, broadcast by CNN on Sept. 16.