Glen Gieschen had a beef with the department over coverage for illnesses he believed were caused by a flu shot.
The 45-year-old former military intelligence officer, whose name was originally banned from publication, pleaded guilty earlier this month to possession of a firearm, possession of a prohibited weapon and possession of a weapon.
Police recovered firearms, body armour, possible bomb-making materials, schematics of the downtown skyscraper and a plan to attack the seventh-floor offices of Veterans Affairs during his arrest last January.
"He sincerely apologizes to all staff of Veterans Affairs Canada for any distress the release of the attack scenario has caused them or their families. This document was never meant to be released to the public," said lawyer Tonii Roulston reading a statement on behalf of her client.
"Mr. Gieschen acknowledges it was irresponsible of him to generate or keep such a document."
She said he is facing the repercussions for what he did.
"He has taken responsibility for his actions and has agreed to pay the consequences and he has entered a guilty plea. He'll be incarcerated and will have a lifetime firearms ban imposed," she said.
Gieschen will be sentenced Jan. 30.
Roulston said she expects his other charges, including making explosives, two counts of careless use/storage of a firearm and unauthorized possession of a prohibited weapon, will be withdrawn at that time.
He was arrested in January after his wife contacted police concerned that her husband might be suicidal.
Gieschen was taken to hospital for treatment under the Mental Health Act. He told officers he had planned to commit suicide.
Court documents say he had been in the military from 2008 until he went on long-term military disability in 2011. He was in a dispute with the department over the coverage of costs for his health issues, which included multiple sclerosis that he blamed on the H1N1 flu vaccine he was given while in the military.
When Gieschen was arrested at his parent's acreage west of Calgary he was dressed in camouflage pants and sleeping with a duffel bag near his head.
Inside the bag was a .40-calibre semi-automatic handgun that was loaded with a full magazine. They also recovered a .308-calibre rifle, a ballistic range finder scope for shooting long distances, a laser site for shooting at close range, night vision binoculars and 1,000 rounds of ammunition.
"Recovered off the accused's laptop was a written plan that contained notes made regarding the reconnaissance of the Bantrel Tower and a plan relating to what the Crown submits was a plan to attack the office of Veterans Affairs," say court documents.
There were also jugs filled with chemicals, including bleach, muriatic acid and chlorine, empty suitcases with metal linings, 16 black sticks with a protruding fuse resembling dynamite sticks, carpenter nails, threaded pipes and six tubes of camouflage face paint.
Police also recovered black gun powder, 16 canisters of bear spray, 25 smoke grenades and a gas mask.
"He did not follow through with a dangerous plot. He didn't have an intention to follow through. He was going to his parents' acreage and that's where his intention was to actually commit suicide," said Roulston.
"I would say it was an idle threat, but in fairness to the facts that we have agreed to, it was very detailed."
Roulston said Gieschen is still receiving treatment at the Southern Alberta Forensic Psychiatric Centre. He was brought to court Thursday in a wheelchair, but declined an opportunity to come into the courtroom.
She said it has been difficult for his family.
"His wife of course is devastated," said Roulston. "This is a family who has never been involved with respect to the criminal justice system to this is all very new to them what's occurred."
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