Declaring their unconditional love for their son, the parents of the man accused of the worst mass slaying in Calgary’s history said they, too, are struggling to comprehend a crime that continues to confound investigators.

Matthew de Grood, 22, is charged with five counts of first-degree murder in connection with the killings of Lawrence Hong, 27, Josh Hunter 23, Kaitlin Perras, 23, Zackariah Rathwell, 21 and Jordan Segura, 22, during a house party celebrating the last day of classes at the University of Calgary.

Speaking publicly Thursday for the first time since the slayings, de Grood’s parents extended their condolences to the families and friends of the victims of Tuesday’s killing spree.

"We are trying to make sense of what happened. We are deeply saddened for what the families and friends of the victims are going through. Your lives have been turned upside down. We know words cannot begin to ease your pain and suffering," said Doug de Grood, the father of Matthew de Grood.

Story continues below this liveblog with the latest from the team of Calgary Herald reporters and photographers covering the slayings and their impact.

The suspect’s mother, Susan de Grood, stood silently beside her husband as he read a statement meant to come from them both.

"We are one voice," said Doug de Grood.

Overcome by emotion and at times visibly struggling with tremors from an unspecified medical condition, de Grood said the accusations against their son have "shocked and devastated" them — but their love for him remains.

"Like any parent can tell you, a love for your child is unconditional, and we love Matthew dearly," he said.

The de Groods’ statement described Matt’s "bright future" as he prepared to enter law school at the University of Calgary this fall.

"Just like you, we struggle to understand what happened," said de Grood, breaking down.

Doug de Grood is a 33-year veteran of the Calgary Police Service who currently holds the rank of inspector, but stressed he was speaking "not as a police officer, but as a parent and as a husband."

However, the elder de Grood’s position on the police service has played a role in the case.

On Wednesday, Alberta Justice announced it has assigned the case to Crown prosecutors from Edmonton to avoid any perception of bias.

On Thursday, Calgary police faced questions about whether an outside agency should take over the homicide investigation.

Spokesman Kevin Brookwell said de Grood’s speedy arrest and charging him with the most serious crime in the criminal code — first-degree murder — are ample evidence the Calgary police homicide investigation is thorough and impartial.

"The cornerstone of our profession is to investigate matters like this without favour or bias," Brookwell said.

"We’re going to, as we do for every file ... investigate this to the infinite detail."

De Grood is being held in custody at the Southern Alberta Forensic Psychiatry Centre pending an appearance in provincial court next Tuesday.

An Alberta Justice official said earlier this week de Grood will likely undergo a psychiatric assessment as the case moves forward in court.