A white former transit officer was convicted of involuntary manslaughter yesterday in the shooting death of an unarmed black man on an Oakland, California train platform in a 2009 encounter that set off days of rioting in the city.

Prosecutors had wanted Johannes Mehserle convicted of murdering 22-year-old Oscar Grant, who was shot as he lay face-down.

The jury had a choice between murder and lesser charges of voluntary and involuntary manslaughter.

The jury found that Mehserle didn't mean to kill Grant, but that his behaviour was still so negligent that it was criminal.

Involuntary manslaughter carries a sentence of two to four years.