Prosecutor refuses to put Trayvon Martin case before grand jury

The prosecutor investigating whether a Florida neighbourhood-watch volunteer should be tried for shooting dead an unarmed black teenager, Trayvon Martin, said last night that she will not bring the case before a grand jury. This means she alone will be responsible for deciding whether his killer should face criminal charges.

Angela Corey announced her decision hours before jurors at a courthouse in Sanford, the Florida city where the shooting took place, were scheduled to begin considering possible cases against George Zimmerman, 28.

In a statement, her office cautioned observers against reading too much into the move, stressing "it should not be considered a factor in the final determination of the case".

However it surprised many observers, given that grand juries, which are made up of members of the public, are often given the job of deciding whether charges should be filed in high-profile cases where police misconduct has been alleged. The citizen panels typically help act as a buffer, protecting authorities from controversy.

Martin's shooting, after which police stand accused of failing properly to interview key witnesses, and of accepting at face value Mr Zimmerman's claim to have shot the unarmed teenager in self defence, certainly falls into that category. It continues to spark widespread protests across the US.

In Sanford yesterday, race-relations campaigners successfully blocked the entrance to the main police station.

Ms Corey must now consider whether there is sufficient evidence to charge Mr Zimmerman with Martin's murder or manslaughter. A neighbourhood watch volunteer who was patrolling a gated community, he claims to have been attacked by his victim, and to have shot him in self defence.