South Korean prosecutors investigating impeached ex-President Yoon Suk Yeol have reportedly found evidence that the disgraced former leader ordered military drones to be sent over Pyongyang.

According to reports in South Korea this week, investigators have obtained audio recordings of communication between the then-president and the military over the alleged drone deployments.

Analysts say the incursions, which reportedly occurred in October 2024, were likely intended to provoke North Korea into a reaction.

That scenario would have provided Yoon with the justification to declare a national emergency and impose martial law, which he eventually did in December.

Yoon, who has since been impeached, is now facing criminal charges for insurrection over his short-lived declaration of martial law.

Why did Yoon allegedly send drones over Pyongyang?

Choo Jae-woo, a foreign policy professor at Kyung Hee University in Seoul, explained that there are "only two reasons" that a president can declare martial law, one of which is "external aggression or an invasion."

"It appears that after provoking the North, Yoon expected a retaliation that he could then use to justify declaring martial law," he told DW.

"But that plan backfired when the North did not respond militarily," he said. Pyongyang protested the incursions but stopped short of responding militarily.

Yoon declared martial law on December 3, saying he needed to protect the nation from "North Korean communist" and "anti-state" forces. He did not provide any evidence for his claims.

Fallout from Yoon's martial law decree

His controversial attempt to use the military to seize control of the government lasted only a few hours.

He was impeached and suspended 10 days later and then arrested in January.

The former leader's charge of insurrection is punishable by life imprisonment or the death penalty, although South Korea has not executed anyone in decades.

Yoon, who was released on bail in March, has denied the charges, saying "martial law is not a coup d'etat" and that his declaration was designed as a "peaceful message" to the nation to highlight the opposition's intentions against the government.

He was questioned again in Seoul on Saturday, and a day later, special prosecutors filed a request for a new arrest warrant for alleged abuse of power, falsification of official documents, violation of the presidential security act and obstruction of official duties. 

According to South Korean media, a hearing to confirm that arrest warrant has been scheduled for Wednesday. Yoon is expected to appear in person to present his arguments before the court.

Authorities say that allegations of treason, which include the dispatch of drones into North Korea, were not included in the charges as they are still being investigated, but they could still be added later.

How did we get to this stage?

In October 2024, there were reports of drones over the North Korean capital, Pyongyang, which is 210 kilometers (130 miles) north of the Demilitarized Zone that divides the Korean Peninsula, on three occasions.

North Korea published purported images of the drones and later claimed to have found the remains of one of the unmanned aerial vehicles (UAVs) that had been shot down after dropping propaganda leaflets.  

In South Korea, the Defense Ministry quickly rejected Pyongyang's claims. But the ministry backtracked a few hours later, saying it could not confirm or deny the reports.

North Korea threatened to carry out retaliatory strikes against the South in response to the propaganda leaflets filled with "inflammatory rumors and rubbish."

While Pyongyang condemned Seoul and said the incident "could be considered a military attack," it did not launch a cross-border retaliation.

The special investigation team set up to look into Yoon's actions in office obtained a recording in which a senior officer of the Drone Operations Command said that his commander had received the order for the operation from "V," the South Korean military's term for the sitting president, the Korea JoongAng Daily reported on July 3.

Further investigations have revealed that two reconnaissance drones were reported missing near the border in October, with a Defense Ministry report saying the reasons for the loss of the vehicles were "unknown."

Yoon's risky gamble

"It is clear that the situation could have been very serious," said Choo, the Kyung Hee University professor. "The exchanges that could have followed may not have been just localized skirmishes close to the border but could have escalated. We were very fortunate that the North decided not to respond."

Dan Pinkston, a professor of international relations at the Seoul campus of Troy University, pointed out that the South's alleged drone intrusion was part of a series of tit-for-tat cross-border exchanges during Yoon's administration, which helped heighten tensions with Pyongyang.

North Korea had been sending surveillance drones into the South and "was jamming GPS signals" close to the border, affecting flights going in and out of Incheon airport, he said.

"There were also groups in the South sending balloons over the border carrying propaganda leaflets, small amounts of food, money and medicine, with the North replying with balloons carrying trash," Pinkston added. 

But Yoon's order for military drones to penetrate North Korea's airspace was more serious, Pinkston said, as this was "a clear violation of the armistice that ended hostilities in the Korean War" (1950-1953). Officially, the two neighboring countries have been at war ever since.

In addition, "it appears it was done without informing the US or the United Nations Command on the border," the professor said.

Drone incursions threatened 'devastating war'

Yoon ordering the incursions could very easily have backfired, Pinkston said. 

"It is hard to understand the thinking behind this decision, but it put the country at the risk of a devastating war," he said.

"This was an extreme move that endangered the territory of South Korea, the people and the nation's assets, all so Yoon could take a tighter authoritarian rule on the reins of government," Pinkston said.

"There is no logical explanation for doing what he did," he added.

Edited by: Karl Sexton