A Toronto police constable is facing criminal charges in connection with the assault of a civilian during the G20.

After months of a difficult investigation which saw officials close and reopen the case twice, police have laid charges against Const. Glenn Weddell with the assault of Dorian Barton during the G20 protests.

Barton, 29, had claimed he was merely a spectator taking photos during the protests on June 26, 2010, when he was tackled to the ground by several officers. He said he was facing officers on horseback and was unaware that a group of marching anti-riot officers was marching towards the crowd he was in, according to the Special Investigations Unit.

He was struck several times during the arrest and suffered a broken right arm among other injuries.

The SIU, a provincial watchdog that investigates cases where civilians are injured in the presence of police, had a hard time with the investigation from the start.

The SIU's initial investigation closed on Nov. 25, 2010 because Barton was unable to identify the officers involved in his arrest. He also couldn't fully explain how the injury occurred. The SIU said there was a lack of conclusive evidence from other witnesses.

In January, the case was reopened after the SIU received several photos of the arrest from a second civilian who was photographing the incident. Twelve officers were interviewed as well as two new civilian witnesses.

However, that still wasn't enough for the SIU to make any conclusions as to who was to blame for the incident. Investigators closed the case on May 16 because they still couldn't positively identify the officer or officers involved in the arrest.

Then, on May 26, the investigation was reopened for a second time when investigators received more information from police. SIU Director Ian Scott said the Toronto Police Service up until that point was not forthcoming with information.

The TPS was asked "on multiple occasions" to explain how they were able to identify the officers involved in the case, he said.

"While the TPS provided the SIU with the name of the subject officer in a timely fashion that, in my view, was not adequate," Scott said in a news release. "We asked for the name of the person who made the identification so that we could take a statement from that individual. That information was not forthcoming."

The case was reopened when on May 25, police provided the name of the witness officer.

At that point, the SIU was able to take statements from three more police officers. Scott said on the basis of information that investigators received during those interviews as well as information gathered during the previous investigations, police were able to lay a charge against the officer.

Weddell is charged with asssault causing bodily harm. He will appear in court on July 21, 2011.

Weddell is the second police officer to face criminal charges in connection with arrests made during the G20.

Const. Babak Andalib-Goortani was charged with assault with a weapon. It is alleged he hit a woman with a baton around Queen's Park on June 26, 2010. He also faces a charge of assault with a weapon in connection with the attack on Adam Nobody, a protester who had his nose and cheekbone fractured during his arrest.

Meanwhile, the third and final public hearing into police behaviour during the G20 will be held Monday at the Scarborough Civic Centre. The hearing is billed as a chance for civillians to share their opinions on what role civillian oversight should play in the policing of major events. Sessions have already been held in Toronto and Etobicoke.