NGO Repubblika staged a protest on Friday evening outside the Attorney General's office and demanded her resignation.
Activists gathered in Valletta a day after Darren Debono, known as it-Topo, in court flatly refused to name any accomplices in the 2010 HSBC heist.
Attorney General Victoria Buttigieg had granted him a plea deal for a shorter prison sentence in exchange for testimony on the case.
"Answer our questions. Explain to us, and explain to us in detail what you did, and then resign," said Repubblika President Robert Aquilina, referring to Buttigieg, as the crowd chanted "out, out out"!
On the evening of the heist in June 2010, armed robbers attempted an audacious heist on HSBC's Qormi headquarters. It ended in a violent shootout with police, during which multiple shots were fired.
Debono was eventually identified as one of the suspects and after the plea deal earlier this year, he was finally set to testify on Thursday, after weeks of legal wrangling about the admissibility of his evidence.
But he expressed fear about snitching on anyone.
As soon as he took the stand, he pointedly refused to name any other accomplices in the heist apart from Vince Muscat il-Koħħu, who is already accused of complicity in the crime.
Magistrate Monica Vella warned him multiple times that he must tell the entire truth and hold nothing back, but Debono pleaded with the magistrate and told her he feared for his wife and children's safety.
"Please your honour, I won’t name them. I don’t want to put my son’s life in danger," the witness pleaded.
His insistence not to name any other accomplices led Magistrate Vella to order his immediate arrest and investigation.
During the protest, Aquilina insisted that the AG had waived a 20-year prison sentence but got nothing in return.
"The Attorney General spared him 20 years in jail, just so that he could remain silent," Aquilina said, adding that Repubblika stands with all police officers and employees at the AG's office who do their job with integrity and are likewise infuriated at this unexpected turn of events.
"She should resign because evidently, the only people who benefited from this plea deal were the criminals who are still running free."
Earlier on Friday, the Nationalist Party held a press conference outside the police headquarters saying that the government has shown that it stands with criminals and not with police officers.
"For almost 12 years, police officers, especially those who took the bullets in the fight for what is right, have been waiting for justice, but this plea deal dropped Darren Debono's most grievous charge: attempted murder on police officers," said home affairs shadow minister Beppe Fenech Adami.
"Now we learn that he will not reveal the names of other accomplices. Why, then, did the Attorney General strike this deal with him? We are now left with a situation where the state allows criminals to have each other's back."
PN candidate Darren Carabott said he lives close to the HSBC in Qormi, and he recalled what he saw that night as a teenager.
"I remember I was at Isle of MTV with my friends and my mother called me to return home. As I walked to the comfort of my home, I could see many police officers on the scene, doing their duty so that I can feel safe at home," he said.
"Now, the government has just thrown away all the respect for their work."
The PN insisted that, come next election, people will need to decide between a government that has stood with criminals while abandoning the police, and a Nationalist Party that stands with people and has tangible proposals for a safer country.
In both Repubblika's protest and the PN's press conference, the names of former Labour minister and deputy leader Chris Cardona and current minister Carmelo Abela came up. The two have faced allegations of playing a role in the heist. Both deny the allegations.