Jane Hughes in New York: "For Louise Woodward, the theory offers new hope"

Two doctors told an American CBS television programme they believed Matthew Eappen died because he had been strangled two days earlier.

Louise Woodward told 60 Minutes, broadcast on Sunday, that it was "only a matter of time" before medical evidence proved she did not kill Matthew.

Matthew Eappen: Medical records under scrutiny

Woodward's lawyers are looking into the doctors' claims, which have been dismissed by one of the prosecutors, Martha Coakley.

"Matthew Eappen died over two years ago, and since then not one person has come forward with the theory that he was strangled - until tonight," said Ms Coakley, a district attorney. "That's because it didn't happen."

Prosecutors said Matthew died in 1997 of injuries consistent with shaking impact syndrome.

Dr Floyd Gilles, a neuropathologist, and Dr Marvin Nelson, a radiologist, reviewed the medical records of eight month-old Matthew at the request of 60 Minutes.

Dr Gilles concluded that Matthew's neck injuries suggested he had been strangled.

Correspondent Jane Hughes: Prosecutors scathing over doctors' findings

He said a neck artery may have been squeezed as much as 48 hours before the child collapsed, causing his brain to swell slowly.

But Dr Douglas Miller, chief of the Neuropathological Unit at New York University Medical Center has rejected this theory.

"I know of no described case of strangulation or carotid artery compression which could leave an infant apparently normal for many hours and then suddenly result in brain swelling and death," he said.

The timing of Matthew's fatal injuries was central to the trial and conviction of Woodward, 21, from Elton, Cheshire, who worked as an au pair at Matthew's home in Boston, Massachusetts.

Woodward was convicted of second-degree murder in 1997

During the trial, 17 months ago, neither prosecution, nor defence witnesses, made any suggestion that Matthew Eappen may have been strangled.

A spokesman for Boston-based solicitors Silver, Glate and Good, who represented Woodward during the trial, said: "One can always seek to reopen a legal case. Legal action is always a possibility.

"If he (Matthew) died of an older injury then of course it is important to the case and the conviction of Louise."

Innocence claim

Woodward was convicted in October 1997 of second-degree murder. She appealed and the judge reduced her conviction to involuntary manslaughter and released her from prison. She is now a law student in London.

She has always said she is not to blame for his death - despite an out-of-court settlement with the baby's parents who threatened civil proceedings.

She told the BBC in January: "Accepting this settlement and agreeing to it is not accepting any liability in any way.

"I will always maintain that I never hurt Matthew and I did not kill Matthew.

"And I will always do everything I possibly can to state that again and again and hopefully one day to prove it."