TUNIS, Tunisia (AP) — More than 3,000 Tunisians, led by the father of an assassinated opposition figure, joined a protest that started as a demonstration against what they described as a "slow" investigation into the death.

The protest, organized on social networks in the country that launched the Arab Spring, quickly turned into a rallying cry against the ruling Islamist party and the country's economic troubles.

Chokri Belaid was shot four times outside his home on Feb. 6, throwing the country into political turmoil as many Tunisians held the government responsible for his death. The prime minister resigned, and the ruling Islamist Ennahadha named an interior minister to take his place.

Belaid's father, Salah, led Saturday's protest. On Thursday, the interior minister announced several arrests in the death, without providing details.