US President Barack Obama and Republican challenger Mitt Romney have closed out their hard-fought battle for the White House, yielding centre stage to voters who face a stark choice on election day between fundamentally different visions for the country’s future.

The neighbourhood watch volunteer who shot dead a 17-year-old boy says he prays daily for the teenager's parents.

US neighbourhood watch volunteer George Zimmerman publicly accused police of covering up the beating of a homeless black man by the son of a white officer more than a year before he shot unarmed teenager Trayvon Martin, it emerged today.

Neighbourhood watch volunteer George Zimmerman has made his first court appearance on a second-degree murder charge following the shooting death of 17-year-old Trayvon Martin.

A neighbourhood watch volunteer was charged tonight with second-degree murder over the fatal shooting of unarmed black teenager Trayvon Martin.

The US Justice Department is to investigate the shooting of an unarmed black teenager by a neighbourhood watch guard following a day of protests over the incident.