The former state trooper shared details Friday of his arrest of McVeigh at the Oklahoma National Memorial Museum as part of the museum's First Person: Stories of Hope series.
McVeigh was charged and convicted for the April 19, 1995, bombing of the Alfred P. Murrah Federal Building, which killed 168 people and left more than 800 injured.
About an hour after the explosion, Hanger stopped McVeigh on Interstate 35 in Perry because his getaway car had a missing license tag. Hanger said when he asked McVeigh to step out of the car, he noticed that McVeigh had a gun holstered to his shoulder.
"I wonder why he didn't try to kill me," Hanger said choked up and in tears. "I know that it was divine intervention. The good Lord put me in the right place at the right time."
"I know McVeigh was a coward, and didn't want to put himself in any personal danger."
Seeing the gun made all the difference, Hanger said.
"If he'd had the gun in his glove box, I may not have arrested him because I wouldn't have had probable cause to search his car," he said. "Well, I don't know. Maybe I would've taken him in. I was a pretty hard-nosed trooper."
After the arrest, Hanger said he began to fear for the lives of his wife Beverly, and their two daughters, who were 15 and 22 at the time. He's still not comfortable with releasing their names to the public.
"Fortunately, we never received any threats, just constant calls from reporters," he said. "You never appreciate your privacy until you don't have it anymore.
"My phone was ringing so much, I literally could not dial out. There was one young man in my community who sold maps of how to get to my house to reporters for $20. Other reporters tried to send us flowers and follow the delivery truck to our house."
Worse than dealing with the media was the initial talk with the victims' families, Hanger said.
"My words to them were: if this individual is responsible, I'm glad to be the first person to put the nail in his coffin," he said getting choked up again. "This was a very heinous crime, very violent; a crime I will never be able to understand."
Hanger said the arrest changed his perspective on life.
"I have a greater appreciation for life," he said in tears. "And I know not to take things for granted."
Hanger also offers advice to officers.
"I tell new officers there is no such thing as a routine traffic stop," he said. "McVeigh was way too calm - it was evil," he said.
The First Person series will last through the first week of September, including discussions with survivors, rescue workers and victims' family members.