Seoul, South Korea (CNN) -- 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.
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.
CNN's K.J. Kwon reported from Seoul and Jethro Mullen wrote from Hong Kong.