SEOUL, South Korea — More details emerged Thursday about the past few months in South Korea of ​​a US soldier who fled across the border into North Korea as the isolated communist country kept quiet about his status.

Private Travis King, 23, second class, spent 48 days in a prison in Cheonan, a city about 50 miles south of the South Korean capital Seoul, after failing to pay a $4,000 fine on charges which included damaging public property, a South Korean government said. an official told NBC News by phone Thursday.

According to legal documents, King was uncooperative when he was detained by officers during the incident last October and caused hundreds of dollars in damage to a police patrol car while yelling profanity about Koreans and the Korean military.

Private Travis King Second Class.
Private Travis King Second Class.through Facebook

“Each day that Mr. King spent in the penitentiary was equivalent to about 100,000 won,” or about $80, said the official, who was not authorized to speak to the media.

The incident threatened to worsen tensions between the US and North Korea, a repressive, nuclear-armed island nation that is still technically at war with the South. The United States does not have an embassy in North Korea, complicating any possible negotiations over King’s return.

King, who was released on July 10, had been escorted by the military to Incheon International Airport on the outskirts of the capital Seoul on Tuesday for possible further disciplinary action in the United States.

Instead, he ended up on a group tour of the Joint Security Area on the heavily fortified border between North and South Korea, where he ran north to the surprise of the tourists who surrounded him.

An airport official told NBC News Thursday that King went to his gate but was missing a travel document needed to board the plane and was escorted by an American Airlines employee.

An American Airlines source familiar with the situation confirmed that King was escorted from the gate.

King’s relatives told NBC News on Wednesday that he had been grieving the death of his young cousin and had acted differently from him.

«It’s out of character,» said his uncle Myron Gates. «I’ve never seen him go down like this, never.»

King is the first known American detained in North Korea in nearly five years.

The United States has about 28,000 troops stationed in the South, a treaty ally that has remained frozen in conflict with the North since the Korean War ended in an armistice rather than a peace treaty 70 years ago this month.

jay blackman, Andrea Mitchell and megan lebowitz contributed.