The 29-year-old former soldier, a decorated gunner in the Gulf war, knew "exactly what the effects of this bomb were going to be," prosecutor Patrick Ryan said.
The victims already had "all the sympathy they can stand," Mr Ryan said. They are lined up in the coming days to demand justice. The jury were to hear from a 10-year-old boy who lost his mother and a rescue worker who held a victim's hand, only to feel the pulse slow and stop.
McVeigh was found guilty on Monday of all 11 counts of bombing, conspiracy, and murder. He faces a minimum of life in prison.
But the penalty stage of the trial, with a witness list of more than 100 people in a hearing expected to last several days, will be bitterly fought. From the start, US officials from President Bill Clinton down have promised the ultimate penalty for the bombers.
McVeigh's defence team, meanwhile, faced with a likely guilty verdict, has long set its sights on keeping him alive. His lawyers include several veterans of death cases in Texas, a state which has put 23 people to death this year alone.
The jury of seven men and five women runs from a grandmother who remembered praying for the victims of the bomb, to computer workers, a maintenance man who reads the Bible once a week, a Vietnam War veteran, and a woman teacher who said McVeigh "looks like a nice kid".
All were passed during the jury selection as "death qualified", meaning they were prepared to consider the death penalty as the law required it, and had no moral, spiritual or personal objections that ruled it out. Most said it was acceptable in some cases.
Judge Richard Matsch said he would allow photographs of maimed survivors to be introduced along with pictures of victims being wheeled into hospitals, and evidence that some of the victims died slowly as gravel and dust filled their longs.
"We can't sanitise this scene," he said. He drew the line, however, at wedding photos and a poem by a victim's father. He promised the defence the chance to grill witnesses on whether they had been influenced by earlier trial testimony.
"A penalty phase cannot be turned into some kind of lynching," he said. "This cannot become a matter of such emotional testimony which would inflame or incite the passions of the jury."
The defence has long faced the problem that McVeigh shows every outward sign of perfect sanity, and though he is said to have been driven by overwhelming hate for the US government, he has the look of a boy-next-door, and has never shown in public the slightest remorse, or even doubt. There was no hint yesterday on whether McVeigh himself would plead for clemency. Instead friends and family will testify to his loyalty and likeability, his small-town upbringing, his parents' divorce and his absent mother, and possibly his failure to qualify for the US special forces after he left the army.
They may also probe the reasons for his anger at the government - the botched siege of armed cultists at Waco, Texas, and the bloody stand-off with white supremacists in Ruby Ridge, Idaho, both causes celebres in the militia circles he travelled. The prosecution yesterday again cited the Turner Diaries, a racist novel of a white supremacist uprising. Mr Ryan quoted passages from the book about a fertiliser bomb that could cause a "shockingly large number of victims."