A man accused of killing an Ontario police officer was found guilty of manslaughter Thursday in a Newmarket courtroom.

Nadeem Jiwa, 23, was found guilty of manslaughter in the death of Det.-Const. Robert Plunkett Thursday evening.

The victim's family had been hoping for a charge of first-degree murder. Reporting from the courthouse, CTV Toronto's Naomi Parness said Plunkett's wife broke down in tears when the jury announced its decision. The family then stormed out of the courtroom.

The jury had deliberated for three days before finding Jiwa guilty of manslaughter.

Parness said the ruling likely came down to whether or not the jury thought Jiwa had known Plunkett was a police officer. Plunkett was dressed in plainclothes when he attempted to arrest Jiwa and another man in August 2007.

The veteran York Regional Police officer was killed while trying to make an arrest during an investigation into a series of airbag thefts. Police had followed two suspects in two vehicles to a residential street in Markham, north of Toronto.

When Plunkett moved in to arrest one suspect, the driver stepped on the gas, pinning the officer in the open driver's side door. Plunkett was dragged for some distance. He later died in hospital from his injuries.

Baseer Mohammed Yousaf-Zai pleaded guilty in 2007 to theft over $5,000, possession of stolen property, two counts of theft and breaching a court order in connection to the case.