KAMPALA, Uganda — Four men who worked in the office of a renegade army general have been charged with plotting to overthrow Uganda's long-serving president, their attorney said Friday, showing the seriousness of the case against Uganda's former spy chief who defected to London.

Ugandan lawyer Ladislaus Rwakafuuzi said all four men —who worked as intelligence agents in the office of Gen. David Sejusa — will face a court martial for alleged "treachery," an offense as serious as treason under Ugandan military law and which carries the death penalty.

He said the charge sheet alleges the four engaged in "activities intended to overthrow the legitimate government of Uganda," the same charge Sejusa is likely to face if and when he returns to Uganda. Sejusa's aides were secretly charged weeks ago and are now detained in a quasi-military facility near the capital, he said.

Sejusa, 58, is a member of Uganda's military high command and a decorated hero of the bush war that brought Ugandan President Yoweri Museveni to power nearly three decades ago. Sejusa is now in self-imposed exile in London after raising concerns that Museveni is grooming his son to become Uganda's next president. The general has since postponed his return to Uganda, saying his life is in danger.

In a letter to the head of Uganda's domestic spy agency, Sejusa had urged an investigation into reports of an alleged plan for the first son to succeed Museveni as president. The letter, which was later leaked to a Ugandan daily, also raised concerns that high-ranking army officers like Sejusa himself risked assassination if they opposed this succession project.

Museveni has never said he sees his son as his political heir. But the son, a senior army officer named Muhoozi Kainerugaba, has been rapidly promoted in recent years, leading many here to believe he is being prepared for high office. Kainerugaba is now a brigadier with full command of the country's special forces, an elite group within the military that protects the president and guards national assets such as oil fields.

Sejusa's succession allegations riveted this East African country where the president has rarely been publicly challenged and sparked a debate about who might replace Museveni, who has been in power since 1986. Uganda has not witnessed a single peaceful transfer of power since independence from Britain in 1962. Some analysts say Sejusa belongs the generation of senior army officers who are disgruntled over the first son's growing influence in the military as Museveni's political power fades, the reason some government officials have accused the general of harboring presidential ambitions.

In recent interviews with The Associated Press, Sejusa has accused Museveni of wanting to keep power within the first family at all costs. He described Uganda's military as a "prison," apparently because serving army officers are barred from participating in electoral politics under the country's military law.

An attorney for Sejusa, Joseph Luzige, said his client would not return to Uganda until he knew precisely what charges he faced. He said the state had not yet made available the details of the state's case against Sejusa.

"They are tightlipped and my client is bitter about it," he said. "Because then he would be able to plan his next course of action."

Some Ugandan military officials have publicly accused Sejusa of spreading propaganda that encourages rifts within the army.