Eileen Mohan's son Chris was one of two innocent bystanders killed in the Surrey Six slayings, the worst gang-related murders in B.C. history. Three trying years later, she is still waiting for justice.

Mohan spoke to CTV News on Saturday next to her son's gravestone. She has grieved there many times before. "It's been a long and difficult and heartbreaking three years," she said.

Six people were murdered in Oct. 2007 at an apartment on East Whalley Ring Road, including four with gang ties. Mohan's 22-year-old son and fellow bystander Ed Schellenberg were apparently killed so there would not be any witnesses.

Six people were subsequently charged in connection with the killings, a fact that Mohan says gives her strength.

"The exceptional results that has been produced in this case is comforting," she said.

One of the accused, Dennis Karbovanec, pleaded guilty last year to three counts of second-degree murder and conspiracy to commit first-degree murder in the massacre.

Matthew James Johnston, James Kyle Bacon, Quang Vinh Thang Le, Cody Rae Haevischer and Sophon Sek are also charged. With dates for pretrial proceedings finally being set, Mohan says she is praying for justice.

"If the accused are held responsible, I'm hopeful they will go away for a very, very long time," she said.

To celebrate the trials' progress, Mohan organized a mass in her son's memory on Saturday night at Surrey's Valley View Memorial Gardens. Several Mounties and politicians, including Solicitor General John Van Dongen, attended.

With a report from CTV British Columbia's Sarah Galashan