From the killing fields of Cambodia to protecting U.S. Presidents: The inspiring story of Leth Oun

PHILADELPHIA (WPVI) -- Leth Oun is one of the millions of Cambodians forever scarred by the traumas of The Killing Fields.

For three years and eight months, he was enslaved, starved and tortured by Pol Pot's murderous Khmer Rouge regime.

Then he came to America and made history as the first native-born Cambodian refugee to join the Secret Service in 150 years.

Now, he's sharing his story with a new book, A Refugee's American Dream: From The Killing Fields of Cambodia to the U.S. Secret Service

He says his goal is to educate people about The Killing Fields, where 1.7 million Cambodians died under Pol Pot's murderous Khmer Rouge regime.

By reliving the painful memories, he hopes people will realize that what happened to him and his family "could happen to anyone in any country."

He was 9 years old when the Khmer Rouge took power. It would be eight years before his family was granted asylum in America.

In the U.S., he finished high school, got his degree, and pursued a career in criminal justice.

He decided to apply for a position with the U.S. Secret Service after 9/11 and has now protected four U.S. presidents and their administrations.

In 2012, he returned to Cambodia for the first time in more than 30 years. This time, protecting President Barack Obama.

This fall, he will reach the mandatory retirement age of 57.

He says he plans to use any proceeds from the book to help the children in his homeland and hopes his story is both a lesson in history and a source of inspiration for young people.

A Refugee's American Dream: From The Killing Fields of Cambodia to the U.S. Secret Service | Website