The assassination of a prominent leftist opposition leader in Tunisia has sparked protests across an already-tense nation teetering on the edge of a political crisis, and left armoured vehicles patrolling the tear gas-choked streets of the capital.
The killing of Chokri Belaid was a chilling escalation of ongoing political violence in Tunisia and brought immediate accusations of government negligence, if not outright complicity - allegations that the ruling party denied.
It was the first assassination of a political leader in post-revolutionary Tunisia, and bolstered fears that the country may face the same chaotic road as other Arab Spring nations transitioning to democracy.
Mr Belaid, a 48-year-old lawyer, was known for his virulent criticism of the Islamist-dominated government and his denunciations of the political violence. He was shot four times at point-blank range outside his home.
His death shook an already tense political scene. The ruling coalition, led by the moderate Islamist Ennahda Party, has been in stalled negotiations with opposition parties to expand the coalition and redistribute ministerial portfolios in an effort to calm the country's fractious politics.
Tunisians overthrew long-ruling dictator Zine El Abidine Ben Ali in January 2011, kicking off a wave of pro-democracy uprising across the Middle East and North Africa which have met with varying degrees of success.
With its relatively small, largely educated population of 10 million, Tunisia has been widely expected to have the best chance of successfully transitioning to democracy.
Its first post-dictatorship election brought to power the moderate Islamists of Ennahda in coalition with two secular parties. But also on the rise have been ultra-conservative Muslims known as Salafis, who have often resorted to violence in their push for strict Islamic law.
The swift and shocked international reaction to Mr Belaid's assassination underlined the global significance Tunisia's politics have for the rest of the world.
"There is no justification for an outrageous and cowardly act of violence like this," US State Department spokeswoman Victoria Nuland told reporters.