Tunisian politician Chokri Belaid knew he was about to be assassinated.
Never one to be silenced, Belaid continued to give media interviews up until the eve of his death, accusing the Islamist-led government of encouraging political violence.
"On February 1, he was at my house. He told us: 'This time, the threats are serious,'" Hedi Abdi, a close friend and member of Belaid's Democratic Patriots Party, said.
Sure enough, the secretary-general of the leftist secularist party was shot four times on his doorstep on February 6.
His funeral was one of the largest outpourings of grief in Tunisian history, with an estimated one million people taking to the street.
The assassination caused the biggest political crisis Tunisia has experienced since the 2011 uprising that brought down President Zine al-Abidine Ben Ali, and has cast doubt over the independence of the country's judiciary and security forces.
"We say there are people who have an intellectual, a moral and a political responsibility in the assassination of Chokri," said Nizar Snoussi, head of the Committee for the Defence of Chokri Belaid, a group of lawyers pushing for justice.
Six months after his killing, a second opposition figure was shot under similar circumstances. Mohamed Brahimi, a pan-Arab leftist, was assassinated on July 25.
Many of the suspects wanted in connection with Belaid's killing are also allegedly linked to Brahimi's assassination, according to the authorities, raising further questions why most remain free. [TO READ MORE ABOUT THE SUSPECTS, CLICK HERE].
On Thursday afternoon, there was an assassination attempt against Mongi Rahoui of the Democratic Patriots' Party, who, as reported previously by Al Jazeera, has been facing similar death threats to those faced by Belaid and Brahimi for some time.
Ennahdha, the Islamist party that is the strongest member of the ruling coalition, has found itself increasingly isolated in the political crisis that has ensued.
The sophistication of the intimidation and surveillance of Belaid is a factor that his friends and family say suggests that those behind his murder may have had access to the state's surveillance apparatus.
Prime Minister Ali Laarayedh, the interior minister at the time of the killing, said at a press conference on February 27 that one of the suspects had confessed to having watched Belaid for about a week prior to the shooting.
Belaid's friends say the threats and surveillance had gone on for more than a year, although it intensified into constant surveillance in the last days before he was shot.
In December 2011, Belaid had begun to be followed by cars and motorbikes, and to receive threatening phone calls and text messages, Abdi said.
By late December 2012 and January 2013, Belaid's two email accounts were hacked, as was his Facebook account. (At the time of this writing, a Facebook fan page dedicated to Belaid still bears the "Hacked" profile picture, uploaded on December 31, 2012, the day when an anonymous hacker took control of the account.)
Belaid had to abandon arranging meetings by text message or phone calls, since details were clearly being shared with a third party.
"Sometimes, we succeeded in getting him away without the people realising it. But then within an hour, wherever we took him, they would be back on his trail," Abdi said. "The only way they could have known where he was, as far as we are aware, is that they were following his phone by GPS."
Only when Belaid experimented with taking the battery out of his phone were they able to shake his pursuers for a fleeting amount of time.
"It's not some isolated terrorists from Chaambi or Tora Bora, it's the state apparatus," Abdi argued, dismissing government claims that the killers are a group of Salafist-jihadists acting in isolation. "The same apparatus that existed under Ben Ali still exists, and Ennahdha is responsible for how it is being used."
Basma Khalfaoui, Belaid's widow, is one of those now experiencing the same patterns of intimidation.
The interior ministry dismissed the allegations that Belaid was being tracked and his communications spied on as unfounded.
"Those are political allegations," Lotfi Hidouri, a spokesman for the interior ministry, told Al Jazeera.
Crisis of confidence
A group of lawyers working on the case say investigators are not doing enough to study the possible complicity of leading figures from Tunisia's ruling Ennahdha party, adding they might bring it to an international tribunal.
The government has stepped up arrests of Salafists implicated in violence in recent weeks. But the move comes much too late to be taken seriously by many Tunisian opposition politicians and activists who have called for the Ennahdha-led government to clamp down on such groups since it came to power in late 2011.
"They're looking for scapegoats to close the case," Abdi said. "But there are people protecting [those who carried out the killings], there are people providing them information."
Chokri Belaid was the leader of the Marxist-Leninist Democratic Patriots Movement. He had played a key role in bringing together the coalition of 12 leftist and pan-Arab parties that came together in November 2012, under the umbrella of the Popular Front.
Assassinated on his doorstep on February 6, the first political assassination in Tunisia in half a century.
Mohamed Brahimi, meanwhile, was a Nasserist. Brahimi had quit his own movement in July 2013 - a few weeks before his assassination on July 25 - saying that it had been infiltrated by Ennahdha. He then formed a new Arab-nationalist party that was to join the Popular Front alliance.Assassinated on his doorstep on February 6, the first political assassination in Tunisia in half a century.
Both Brahimi and Belaid had denounced what they argued was Ennahdha's ties to the US and to Gulf states. Both had also criticised Nidaa Tounes, the centre-right secularist party led by Beji Caid Essebsi.
Assassinated on July 25 in front of his wife and daughter.
Al-Hadi al-Qaderi, the chief of staff of the justice ministry, told Al Jazeera he was unable to comment on the investigation because the case was still ongoing and subject to confidentiality.
"The justice ministry has nothing to do with these investigations as they are being conducted by a judge who is still working on the case," al-Qaderi wrote in an email.
The investigation comes as many members of the judiciary battle what they say is an unprecedented level of political interference.
Raouda Laabidi, head of the Tunisian Magistrates' Union, said the independence of the country's judiciary had been seriously undermined by political prying.
"The judiciary … is experiencing the darkest period in its history," she told Al Jazeera.
Laabidi said judges and lawyers had been attacked. "It's intended to silence people, but we will not be silenced," she said.
Snoussi, head of the Committee for the Defence of Chokri Belaid, said he wants allegations that leading figures of the ruling party might be in some way linked to the killing to be more thoroughly investigated. The committee wants to see Rachid Ghannouchi, the president of Ennahdha, and Habib Ellouze, a member of the party's executive bureau who has been particularly vocal in his support for Salafist groups, among other key political figures, interrogated.
Ennahdha has officially condemned the assassination as "a hateful crime that was aimed at aborting the revolution," and says the opposition is politicising the investigation. The party declined to comment for this article.
Ghannouchi has started legal proceedings against opposition politician Samir Bettaieb after the writer accused him of responsibility for Belaid's death. The Ennahdha president said recently, however, he would withdraw the case against Bettaieb.
Ellouze, meanwhile, has taken journalist Zied El Heni to court for defamation over a story accusing him of ties to a "parallel security apparatus" within the interior ministry, allegedly linked to Belaid's killing.
El Heni has called for the Belaid investigation to be moved to a military tribunal, given the potential implication of officials within the interior and justice ministries.
Prime Minister Laarayedh was summoned three times for questioning, and it was only after coming under fire from the media that he appeared before an examining magistrate on April 25.
Belaid had clashed in public with leading Ennahdha figures, particularly Laarayedh, and had said they were complicit in rising tensions because of their failure to take action against the perpetrators of political violence.
Laarayedh accused Belaid and other leftists of leading an "insurrection" against the government.
“Chokri Belaid is calling for acts of violence. Everywhere he goes, there is disorder and destruction,” the then-interior minister Laarayedh said on November 29, 2012.
Laarayedh's comments came three weeks after Belaid had spoken out against attacks on his party's office in Jendouba, and death threats made against himself and others in his movement.
"Even in the month of November 2012, the interior minister, Ali Laarayedh, incited his allies against Chokri Belaid," Snoussi said.
Snoussi said there has been political interference in the investigation and the magistrate was “too passive” when he finally did question the prime minister. Laarayedh's office said it could not comment on the case since the investigation was ongoing.
President Moncef Marzouki, whose Congress for the Republic Party is an ally of Ennahdha, has already given his testimony to the examining magistrate, denying he had warned of Belaid's impending assassination.
This contradicts a statement Belaid made in a press conference days before his murder: that Marzouki had warned him that authorities had information he was about to be assassinated and offered him security.
And then there is the matter of the ballistics report. The examining magistrate has repeatedly told Snoussi and his colleagues there were no qualified ballistics experts in Tunisia, and it was necessary to have a foreign laboratory complete the analysis.
For six months there was no news. Then, less than 12 hours after the killing of Brahimi, a Tunisian ballistics expert appeared at a press conference given by the interior minister. The expert alleged that Brahimi and Belaid had been shot dead with the same weapon. But the lawyers of the deceased have yet to see any official ballistics report.
Patrick Baudouin, honorary president of the Paris-based International Federation for Human Rights (FIDH), said the Tunisian investigation has, so far, fallen short of international standards.
"We have serious doubts about the political will to find out who ordered this killing," said Baudouin, who is also a member of the Committee for the Defence of Chokri Belaid.
Amna Guellali, Human Rights Watch's researcher on Tunisia and Algeria, said the many incitements to violence from Salafists - without any investigations or consequences - has fuelled the perception that Ennahdha had been "coddling the perpetrators of violence".
"To be sure, there is some kind of responsibility from the government, in terms of the laxity with which it has confronted the calls to violence, which have been escalating in Tunisia since the [October 2011] elections," she said.
This is not just about isolated political assassinations, activists say, but a campaign of intimidation targeting opposition politicians, journalists, writers and artists that has been underway since late 2011.
"Prior to the [US] embassy attack [in September 2012], there were at least two or three attacks a month against members of the opposition who didn't belong to the Troika [the ruling coalition], or against cultural figures. And in most of these cases, there wasn't any judicial process opened by the authorities," said Professor Alaya Allani, a historian and researcher on Islamist movements at the Maghreb at Manouba University in Tunis.
Every Wednesday, a group protests outside the theatre on Avenue Habib Bourguiba demanding to know "Who killed Chokri Belaid?".
Belaid's friend Abdi summarised the protesters' frustration.
"Considering what the practices that have been inherited [from] the former regime - no democracy, no transparency - we are not under the illusion that this is a serious and transparent operation to arrest the suspects."
Follow Yasmine Ryan on Twitter: @YasmineRyan