A Toronto police officer told a trial that when he saw the body of Jane Creba lying on the roadway, he thought she was dead.

"I didn't think there was anything I could do for her," Const. Brian Callanan testified on Friday.

He had been working security at the now-defunct Sam the Record Man store at Gould and Yonge Streets on Boxing Day 2005.

He heard two separate volleys of shots about three seconds apart. He radioed in that shots had been heard fired, then left the store to cross Yonge Street to the shooting scene, the murder trial of "J.S.R." heard Friday.

Callanan stepped into a zone of "sheer pandemonium and mayhem."

He described hundreds of screaming people running, some ducking and others being trampled. Creba was lying on the roadway. A female passerby was helping her. The court has heard a bullet first struck Creba in the back then exited at the base of her throat. She had likely been trying to duck.

Callanan noticed that when paramedics and firefighters arrived, the crowds started to return.

"As fast as they left, they came back. Everybody wanted to have a look. They wanted to have a look at the victims and the shell casings," he said.

On Thursday, Const. Angela Kahnt testified that she saw some young onlookers taking photos of Creba with their cellphone cameras.

J.S.R. -- now 20, but 17 at the time of the incident so he's being tried as a young offender -- has been linked to a gun allegedly used at the crime scene. But he is not accused of firing the shot that killed Creba.

However, recent advances in Canadian criminal law mean that someone involved in a gunfight can be charged with murder if another person returns fire that kills a bystander.

J.S.R. faces one charge of second-degree murder in this trial, along with six counts of attempted murder and five weapons charges.

J.S.R. is the first of nine people to go to trial in the case. Seven of those awaiting trial are adults and one is a young offender.

On Monday, a cab driver is expected to testify about a tip he gave that led to J.S.R. being arrested 40 minutes after the shooting at Castle Frank subway station.

With a report from CTV Toronto's Chris Eby