Nanny is portrayed as a pitiless killer

Louise Woodward listened tremulously to a tape-recording of the emergency call she made when baby Matthew Eappen went into convulsions. David Usborne was in court in Boston on the first day of her trial on first degree murder charges.

The 19-year-old British nanny facing first degree murder charges in Boston in the death last February of the baby boy in her charge, Matthew Eappen, was portrayed by prosecutors yesterday as a pitiless killer who had inflicted injuries on the child that were "extremely atrocious and cruel".

In vivid opening statements, assistant district attorney Gerry Leone repeatedly told jurors that the eight-month-old child had become incapacitated and died days later in hospital because of "injuries caused by violent slamming against a hard surface."

Previewing a case for the prosecution, which will describe a young nanny at the end of her tether with a child who would not settle, Mr Leone said that the injury had been inflicted in the bathroom of the family home. Matthew's parents, Deborah and Sunil Eappen, are both doctors. The "slamming" of the child's head, he said, was an "action that anyone would know would cause a little eight-month-old boy to die."

A tape-recording of Louise, apparently in a state of panic, ringing the emergency services was entered as a first exhibit by the prosecution. Pleading for assistance, she was heard to say: "Help ... he's making gurgling noises ... help, what should I do?... I think he puked. His face is going violet ... Oh, my God."

For the defence, Andrew Good said he would demonstrate over the course of the trial, that may last three weeks, that Matthew in fact died from injuries that had been sustained, but not detected, in days prior to the day in question. "When they say what happened, they will not be able to prove it happened," Mr Good said.

Also on the defence bench was Barry Scheck, one of America's best-known lawyers, who made headlines as part of O J Simpson's so-called "dream team" of defenders.

If they fail to avert a guilty sentence for Miss Woodward, she could face a sentence of life imprisonment without parole.

Countering an assertion by the prosecution that Matthew had suffered injuries commensurate with falling onto his head from a first floor window, Mr Good said this would be shown to have been impossible. Such a trauma, he said, would surely have left the head "smashed and destroyed", whereas on his admission to hospital Matthew showed no external signs of injury, "not a mark on him".

The defence will argue that an earlier injury caused a slow leaking of blood vessels in Matthew's head that eventually created the pressure that led to his death. To support their case, the defence will present several medical experts and will also attempt to show that Matthew had a fractured wrist, also apparently sustained several days before 4 February.