By Simon Watts BBC News, Miami

Ojeda Rios' supporters took to the streets after news of his death

FBI chief Robert Mueller has launched an investigation into the death of a fugitive Puerto Rican rebel leader in a shoot-out with US federal agents.

Filiberto Ojeda Rios was wanted for a bank robbery in the mainland US in 1983, and died in a gun battle at a farmhouse in Puerto Rico on Friday.

The incident has caused anger on the Caribbean island, which is an American commonwealth territory.

Hundreds of people attended Monday's funeral procession for Ojeda Rios.

Unanswered questions

The FBI has come under heavy criticism in Puerto Rico for the way its agents handled the operation to capture Ojeda Rios.

Many people there have the impression that Washington doesn't apply the same standards on the island as on the mainland.

In response to demands from Puerto Rico's politicians, the FBI has now promised an independent inquiry into what happened during this shoot-out.

It will focus on two questions: did Mr Ojeda Rios fire first or was it the FBI agents?

And why did the FBI wait 24 hours before entering the property.

Ojeda Rios was lying on the floor injured, and his relatives say the delay was responsible for his death.

Campaign for independence

The FBI were trying to arrest Ojeda Rios over the most notorious action in the campaign for independence by his small rebel group, the Cane Cutters.

It was an armed robbery in the US state of Connecticut in 1983, which the authorities consider an act of terrorism because it helped fund the group's activities.

Although many people attended the funeral procession on Monday, the Cane Cutters never attracted much public support.