The BBC's Jeremy McDermott: "The capital was in a state of shock after hearing the news"

Garzon, who had been working to forward peace efforts with leftist rebels, was shot dead on Friday as he drove to the Bogota radio station where he presented a morning show.

He will be buried on Saturday after a funeral Mass at the National Cathedral.

A BBC correspondent in Bogota, Jeremy McDermott, likened the outpouring of grief to that for Princess Diana in Britain and John F Kennedy Junior in the United States.

Friends and colleagues gathered close to the murder scene

The traffic lights where the motorcycle assassins pulled alongside the comedian's jeep and pumped five shots into his head and chest is covered in flowers and tributes.

In an honour usually reserved for top politicians, Garzon's body was allowed to lie in state in Congress.

Hundreds of Colombians gathered outside, chanting for an end to political violence and waving white handkerchiefs.

"This man was a symbol of honesty, of courage, of truth, " said one of the thousands of fans paying their final respects.

Reward

The government has announced a reward of 500m pesos ($270,000) for information leading to the killers' arrest.

Students, their hands painted green for peace, protest against the killing

President Andres Pastrana, a long time friend of Garzon's, said: "This is contemptible from all points of view and once again I want to reiterate that Colombians are tired of this type of violence and we must look for reconciliation."

The president had recently appointed Garzon to a peace team looking at ways to start talks with the National Liberation Army (ELN), the country's second largest rebel group.

Right-wing paramilitaries were initially blamed for the assassination, but have issued a denial.

The largest rebel group, the Revolutionary Armed Forces of Colombia (FARC), is also under suspicion following reports that its relationship with Garzon had soured.

The government said 600 motorcycles fitting the description of the one used in the killing had been impounded for investigation.

Death threats

The comedian, who was gunned down shortly after 6am local time a few blocks from Radionet, the station where he worked, was best known for his stinging send-ups of Colombian personalities.

Garzon satirising Bogota's mayor, Antanas Mockus.

But he also liased with leftist rebels to try to secure the release of kidnap victims and had organised guerrilla news conferences in a southern rebel-controlled area.

On Friday, he had been due to leave on a trip to help negotiate the release hostages held by the ELN.

Colleagues said Garzon had told them, as recently as Thursday, about receiving death threats from right-wing paramilitary militias.

Garzon's sister, Marisol, said he had become more careful about his movements lately, although he refused bodyguards.