Argentina’s President Cristina Fernandez de Kirchner, sitting in a wheelchair, addresses the nation during a televised speech in Buenos Aires, on Jan. 26, 2015. (Handout/Argentine Presidency via Reuters)

They use fake names, drive cars with false documents, carry unregistered guns.

They work for an agency with a broad mandate, like a mix of the FBI and the CIA, with a secret budget and vague objectives that allow them to investigate almost anything. Decades after the most notorious abuses during Argentina’s dirty war, the spy service here has yet to shed its bad reputation.

So when President Cristina Fernández de Kirchner made a surprise announcement Monday night that the Intelligence Secretariat — better known by its old acronym, SIDE — would be dissolved, its spies’ activities restricted and wiretapping authority moved to the attorney general’s office, Argentines acknowledged that reform was long overdue.

Yet the reaction to the announcement — which came as the president was addressing the shooting death of a prosecutor in the country’s most notorious terrorism case — has been more complicated, because many people suspect that Fernández has mixed motives, including concentrating power around her office and shielding her allies from investigations.

And former employees of the roughly 2,000-person spy agency warned that the disruption — if Fernández’s bill is able to move through Congress — of dismantling one security agency and forming another could put the country at risk.

“It was an announcement for dramatic effect, with huge consequences for national security,” Miguel Angel Toma, who headed the Intelligence Secretariat from 2002 to 2003, said in an interview. “International trust towards Argentine intelligence will diminish. Getting rid of the best intelligence officers that work on terrorism will create a true party for terrorists in Argentina.”

Fernández’s proposal is intertwined with the country’s most famous terrorism case: the 1994 bombing of a Jewish cultural center in Buenos Aires that killed 85 people. Over the years, Argentine intelligence officers took a lead role in investigating that case and arriving at the conclusion that senior Iranian officials ordered the attack. One of those investigators was Antonio “Jaime” Stiusso, a powerful former head of operations for the agency who worked there under several administrations, including the dictatorship.

“He’s managed all the principal investigations for Argentina,” said Gerardo Young, a journalist and author who has written a book on the country’s intelligence service. “He’s a man who’s linked throughout the global world of espionage.”

In 2004, prosecutor Alberto Nisman took over the bombing investigation, working closely with Stiusso on the case.

This month, Nisman announced that he had concluded that Fernández, her foreign minister and other prominent allies had conspired to absolve Iranian officials of responsibility in the bombing in order to boost trade between the two countries. His nearly 300-page report included wiretap transcripts of Fernández loyalists allegedly discussing the deal with Iranian agents. Five days later, Nisman was found dead in his apartment from a gunshot to the head.

Fernández, in speeches and written statements after Nisman’s death, has singled out this type of collaboration between prosecutors and intelligence officers as something she wants to change.

“We want to bring an end to this carousel made up of prosecutors, judges, journalists and intelligence agents,” she said in her televised address Monday.

Fernández — who shook up the agency, appointed a new head and removed Stiusso amid growing tensions last month — now essentially equates the bombing investigation with a spy plot to weaken her government. She has described Nisman’s arguments as “absurd” and has publicly cast blame on Stiusso and another of Nisman’s colleagues, Diego Lagomarsino, for manipulating Nisman into making the accusations against her and then possibly killing him.

Lagomarsino has been charged with giving Nisman the gun that was found by his body but not with murder. Stiusso has not been charged and has not spoken publicly since the scandal began.

The country’s civilian spy agency was formed just after World War II by President Juan Perón, and early on it participated in helping Nazis escape to Argentina. During the military dictatorship that followed, it functioned as a secret police force, at a time when Argentina became infamous for brutal state repression and “disappearing” its citizens. Despite a name change in 2001, it’s still known for spying on domestic opponents and businessmen, and carrying out other politicized missions.

“The SIDE operates in a way that is totally hidden from society,” Young said. “It’s an organization that’s absolutely outside and parallel to the state, under no one’s control.”

Some have criticized Fernández’s proposal for granting sole wiretap authority to her attorney general, Alejandra Gils Carbó, considered a staunch partisan. But others argued that the attorney general’s office is a large public institution with a known budget and payroll and some oversight, more than can be said about the intelligence service.

The president’s political opponents on Tuesday vowed to try to block her proposal from moving through Congress, although her party has the majority.

“They want to show this is an act of high democracy, but it isn’t,” Hermes Binner, an opposition congressman, said on Argentine radio.

One prominent opponent, Mauricio Macri, the mayor of Buenos Aires and a potential presidential candidate in the election later this year, said at a news conference that the intelligence service over the past decade has “conveyed to us more fear than tranquility.”

“The SI is not going to change with a modification of its name. Change will happen if power is exercised differently,” he said. The agency “has to be a place that works to protect us. We need to change the way we do politics. We’re not comfortable with this change because we don’t trust it.”