When he was asked about the people inside, he compared them to the storm- troopers from the movie Star Wars - even if they were innocent, they worked for an evil government.
Mr McVeigh went on trial for his life in a Denver court yesterday, two years after his arrest and one day after his 29th birthday.
The prosecutor, Joseph Hartzler, portrayed the former Gulf War soldier as the author of a monstrous act of hate, who set out to see "rivers of blood flow in the streets of America".
"We're prosecuting him because his hatred boiled into violence," Mr Hartzler told a jury of seven men and five women.
The trial got under way in a heavy snowstorm with remarkably little fanfare. The courtroom was closed to television cameras and Judge Richard Matsch barred anyone in the case from talking to the press.
The public queue for courtroom places was short and orderly. Mr Hartzler, a victim of multiple sclerosis who spoke from a wheel chair, admitted yesterday that there might be unanswered questions in the Oklahoma City bombing.
He told the jury that because of a widening investigation of the FBI crime lab, an independent British chemist, Linda Jones, would play a leading role in describing how the bomb was made.
But in a bare two-hour opening, in a case expected to last three to six months, he spliced visions of a tragedy in a sunny spring day in Oklahoma against the "twisted purpose" of a man who hoped to launch a second American revolution with an act of anti-government terror.
He said McVeigh was going to carry out his plan "by murdering innocent men, women and children ... to see blood flow in the streets of America."
"The only reason they died ... is that they were in a building owned by the federal government that Tim McVeigh hated so much. He chose to take their innocent lives to serve his twisted purpose."
Stephen Jones, for the defence, also chose to make an opening statement yesterday.
He called the bombing the "Pearl Harbour" of his generation, declared his client innocent and immediately attacked the government for cutting short its investigation.
But Mr Hartzler, it appeared, had left a hard act to follow.
He began with the children who died in a day-care centre on the second floor of the Alfred Murrah building. He described a mother who had just dropped off her 16-month-old child turning to see his hands pressed against the window - the last time she or any other parents would see any of the 19 child victims alive.
Months before the bombing, Mr McVeigh had selected the target, Mr Hartzler said. He stole detonators from a rock quarry, purchased 50lb bags of fertiliser, and used Campbell soup tins to model the barrels of home-made explosives. Arrested on the morning of the blast as he was driving out of Oklahoma City, he had the ear plugs that he allegedly used to protect his eardrums in his pocket.
On the day of the bombing, Mr McVeigh was wearing a T-shirt printed with a photograph of Abraham Lincoln. Under the picture were the Latin words that the assassin John Wilkes Booth had shouted as he shot Lincoln. "The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants," it said on the back.
Mr McVeigh had planned the attack as revenge for the deaths of David Koresh and his cult followers at Waco, Texas, Mr Hartzler said.
He was convinced that Waco was a signal that the US government had declared war on his own people, and believed that agents from the bureau of Alcohol, Tobacco and Fire- arms were based in Oklahoma City.