A statement from the tribunal in Blida, south of Algiers, said the prosecutor appointed a judge to investigate the ex-president's younger brother Said Bouteflika, Gen. Mohamed Mediene and Gen. Athmane Tartag.
They are being investigated for "plotting against the authority of the state" and "attacking the authority of the army," the statement said. The arrest of three key figures from the era of Bouteflika put a new dent in the crumbling power structure of this gas-rich North African nation, which is in the midst of a deep political crisis triggered by a popular but peaceful revolt.
The ailing Bouteflika, 82, resigned April 2 under pressure from the army and weeks of street protests after two decades in power. His bid to seek a fifth presidential term had sent defiant citizens into the streets.
A dramatic video aired on state television Sunday night showing the three men climbing the steps to the military tribunal. Said Bouteflika, 61, was rarely seen during his brother's presidency and the two generals almost never, giving special impact to the video.
The younger Bouteflika was widely viewed in Algeria as the man at the center of a political system that enriched the nation's industrialists while young Algerians suffered high unemployment. He has been accused of usurping presidential powers after his brother's 2013 stroke.
Mediene, best known as Toufik, was for 25 years in charge of military intelligence service DRS and one of Algeria's most powerful men until he was forced to resign in 2015. Tartag headed the DSS state security service until last month, when he quietly stepped down after Bouteflika resigned.
The powerful army chief, Ahmed Gaid Salah, had publicly accused Toufik of plotting against the popular revolt, saying in an April 16 speech that he had "irrefutable proof" and warning of legal action if he did not stop.
Without naming him, Gaid Salah denounced Said Bouteflika in another speech, condemning "plots and abject conspiracies, fomented by a gang that made fraud, wrongdoing and duplicity its vocation." A wider anti-corruption campaign, encouraged by the army chief, is in progress with several top industrialists currently jailed.
However, Gaid Salah himself is taking criticism from some citizens wary of his direct role in the course of events, fearing the military, which has long run the country from behind the scenes, will usurp the people's revolt.
Meanwhile the man officially in charge of Algeria, interim leader Abdelakader Bensalah, gave a speech Sunday night aired on national television appealing for dialogue and cooperation ahead of a July 4 presidential election.
He promised that the newly elected president would undertake "deep political reforms" as protesters have demanded, and reiterated accusations that unspecified foreign forces are threatening Algeria's stability.
Associated Press writer Aomar Ouali reported this story in Algiers and AP writer Elaine Ganley reported from Paris.