Story highlights South Korea's intelligence agency offers an analysis of Jang Song Thaek's execution

It suggests business-related disputes may have played a role in his downfall

The agency says Jang may have refused an order from Kim to solve the disputes

The agency's analysis was relayed in comments by a South Korean lawmaker

Did business disputes play a role in the dramatic demise of Kim Jong Un's once powerful uncle?

That's what South Korea's main intelligence agency appeared to suggest Monday in comments relayed by a lawmaker.

The uncle, Jang Song Thaek, was considered instrumental in Kim's rise to power two years ago. But Kim turned his back on the man once seen as his protector in spectacular fashion earlier this month, having him executed on charges he tried to overthrow the government.

Jang's death was announced in an unusually public declaration from the secretive state.

Analysts have put forward a variety of reasons that may have led to Kim's decision to turn against his uncle and to publicize his execution. Some suggested there may have been a struggle for power between Kim and Jang.

Photos: Jang Song Thaek: From adviser to 'traitor' Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – In an image taken from footage shown by North Korea's KCTV and released by South Korea's Yonhap news agency on December 9, 2013, Jang Song-Thaek is reportedly being dragged away from his chair by two police officials during a meeting in Pyongyang. North Korea confirmed on December 9 that the powerful uncle of Kim Jong-Un, the nation's leader, had been removed. New reports from North Korea say that Jang has been executed. Hide Caption 1 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Japanese lawmaker Antonio Inoki, left, Jang Song Thaek and Kenshiro Matsunami, a former Japanese lawmaker, hold a meeting in Pyongyang, North Korea, on November 6. Jang Song Thaek was regarded as the second most powerful figure in North Korea. Hide Caption 2 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Kim Jong Un, left, and Jang Song Thaek walk through a cemetery for Korean War veterans on July 25 in Pyongyang, North Korea, marking the 60th anniversary of the signing of the armistice that ended hostilities on the Korean peninsula. Hide Caption 3 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Chinese President Hu Jintao, right, greets Jang in Beijing on August 17, 2012. Jang met China's President and Premier in an effort to improve the relations between the two countries after Kim Jong Un irked Beijing with a rocket launch soon after taking power. Hide Caption 4 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Kim Jong Un walks past his uncle after reviewing a parade of thousands of soldiers commemorating the 70th birthday of the late Kim Jong Il in Pyongyang on February 16, 2012. Hide Caption 5 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Jang attends a meeting on developing the economic zones in North Korea, in Beijing, on August 14, 2012. Hide Caption 6 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Jang follows Kim Jong Un during the funeral procession for Kim Jong Il in Pyongyang on December 28, 2011. Hide Caption 7 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Jang is seen with Kim Jong Il, right, and Naguib Sawiris, center, the executive chairman of Cairo-based Orascom Telecom, at an undisclosed place in North Korea on January 23, 2011. Hide Caption 8 of 9 Photos: Jang Song Thaek: From adviser to 'traitor' Jang Song Thaek: From adviser to 'traitor' – Jang, far right, appeared with Kim Jong Il and other officials during an inspection of the Mt. Ryongak Recreation Ground in Pyongyang, in an image released on January 18, 2009, by the official Korean Central News Agency. Hide Caption 9 of 9

Pinning down the truth may prove impossible for a reclusive regime like North Korea. But agents at South Korea's National Intelligence Service, which broke news of Jang's initial fall from power before North Korea announced it, are nonetheless trying to get to the bottom of the situation.

The agency briefed lawmakers of a parliamentary intelligence committee Monday about what it thinks was behind Jang's downfall.

The head of the agency, Nam Jae-joon, played down the theory of a simple power struggle between Jang and Kim, said Jeong Chung-rae, a lawmaker from the United Democratic Party who attended the briefing.

Based on the intelligence agency's analysis, Jang's aides in certain government agencies involved in business projects, including coal and trade, overstepped their authority, creating conflicts with other agencies, the lawmaker said.

The agency believes Kim may have stepped and demanded that the disputes be resolved -- an order Jang apparently declined to carry out, Jeong said.

That decision may have cost Jang his life.

"Jang was purged for violating the supreme leadership, according to the NIS report," Jeong said.

North Korea state media made some references to business wrongdoing by Jang in their expansive recounting of his alleged crimes.

"The Jang group put under its control the fields and units which play an important role in the nation's economic development and the improvement of people's living in a crafty manner, making it impossible for the economic guidance organs including the Cabinet to perform their roles," the state news agency said in the official report announcing Jang's removal from his posts.

It said he had sold off "precious resources of the country at cheap prices."

Analysts have said that Jang, who was close to Chinese officials, was believed to have a more open mind about capitalist forms of economic development than hardline members of the regime.

By discounting the theory of an outright power struggle between Kim and Jang for control of the regime, the South Korean intelligence agency said it believes Kim's position at the top is stable.

The regime is still investigating many of the agencies under Jang's control, the NIS said, according to Jeong.

It also said that it believed that images that showed Jang being dragged out of a large meeting were part of a choreographed event to demonstrate Kim's power.