A discredited engineer who declared a northern Ontario mall structurally sound just weeks before its roof caved in killing two women was charged Friday in what police described as a "challenging investigation."

Ontario Provincial Police said 64-year-old Robert Wood faces two counts of criminal negligence causing death and one count of criminal negligence causing bodily harm in connection with the June 2012 collapse in Elliot Lake.

"This was a unique, complex and challenging investigation which took considerable time to process evidence and being precise in the application of criminal law," said Detective-Superintendent Dave Truax.

"Wood was an engineer who was involved in the inspections of the building."

Dave Traux

OPP have laid two counts of criminal negligence causing death, and one count of criminal negligence causing bodily harm against the engineer who last inspected the Algo Centre Mall before its roof collapsed. OPP Detective Superintendent Dave Traux says police hired engineers to help with the investigation. (Yvon Theriault/Radio-Canada)

Truax wouldn't say if charges against others were pending but emphasized that the criminal investigation was ongoing.

A judicial inquiry into the collapse at the Algo Centre Mall has heard the roof of the poorly designed structure leaked from the beginning, and decades of water and salt penetration caused severe rusting of its steel support structure.

The inquiry also heard that Wood declared the centre structurally sound just weeks before it collapsed.

Inspection report changed

In a 2011 conversation relayed to the inquest, Wood was cited telling a prospective buyer it would cost $1.5 million to fix the mall's roof and reportedly warned the structure had to be fixed or the roof would cave in.

However, Wood told the inquiry he could barely recall any such conversation.

The inquiry then heard that subsequently, in May 2012, Wood told the mall's owner that steel supports at the shopping centre showed surface rusting, but were otherwise "structurally sound."

Robert Wood

Engineer Robert Wood is seen testifying at the Elliot Lake Inquiry in June of 2013. Provincial police have criminally charged Wood, 64, with two counts of criminal negligence causing death and one count of criminal negligence causing bodily harm. He was arrested today in Sault Ste. Marie. (CBC)

The assessment followed an inspection of the property in which Wood noted "no visual distress."

Wood later admitted changing his final May 3, 2012, inspection report after he and his partner signed off on it.

The changes included removing photographs he had taken in a mall store showing yellow tarps strung up to collect water leaking from the roof and a corroded steel beam. He also removed a reference to "ongoing" leakage.

The changes were made at the request of the mall owner, Wood told the inquiry, as the man was apparently unhappy the mall would look bad when he was trying to get refinancing for it.

Wood continued to practise

Wood was stripped of his professional engineering licence in November 2011 after admitting to misconduct unrelated to the mall.

He continued to practise as a "graduate" engineer and owner of M.R. Wright based out of Sault Ste, Marie, Ont. with restrictions on what he could do. His 40-year career ended shortly after the mall roof collapse.

Doloris Perizzolo, 74, and Lucie Aylwin, 37 were killed in the collapse. While an autopsy showed Perizzolo died quickly, Aylwin is believed to have lived longer.

elliot-lake-mall

A judicial inquiry into the collapse at the Algo Centre Mall, in Elliot Lake, Ont., heard the roof of the poorly designed structure leaked from the beginning, and decades of water and salt penetration caused severe rusting of its steel support structure. The inquiry also heard that Robert Wood declared the centre structurally sound just weeks before it collapsed. (CBC)

The OPP began their investigation shortly after part of the Algo Centre Mall's parking deck caved in.

Wood is expected to appear in court in Elliot Lake on March 25. Police also say their investigation continues, and did not rule out more charges in connection with the mall roof collapse.​

A judicial inquiry into the collapse at the northern Ontario mall concluded last October after hearing from 125 witnesses over 117 days. A report is due before Oct. 31.

The inquiry heard the poorly designed and built mall had leaked from the beginning, but no one ever tackled the expensive-to-fix problem substantively and decades of water and salt penetration caused extreme rusting.

Commissioner Paul Belanger cited the length and complexity of the hearings, along with having to sort and analyze a large volume of materials, for the time it is taking to produce his report.