PIERRE, S.D. - A former Hyde County farmer serving a life sentence for murdering his wife continues to argue that he should get a new trial because his conviction was based partly on the testimony of an expert witness who has been caught lying about his credentials.

David Aesoph has lost his appeals in state courts, but he now wants a federal judge to order that he be given a new trial for the 1999 murder of his wife, Tania, 50.

Aesoph argues that his wife died after she fell down a flight of stairs in their home 30 miles northeast of Highmore. A pathologist testified that the woman was beaten and strangled.

One of the prosecution witnesses was Saami Shaibani, a physicist who told the jury it was against the laws of physics for the woman to have fallen down the stairs as her husband claimed.

Shaibani testified for the prosecution in a number of murder cases around the nation as an expert on what he called injury mechanism analysis, a combination of physics, trauma medicine and engineering. At least one conviction, in Wisconsin, has been overturned because he misrepresented his credentials by saying he was a clinical associate professor at Temple University.

South Dakota Attorney General Larry Long said the problem involving Shaibani's credentials has been raised in Aesoph's appeals in state court. "So far, that hasn't been helpful to him, to Mr. Aesoph," Long said.

The state contends Shaibani's statement about his affiliation with Temple University has not been definitely established to be false, Shaibani's testimony was not critical to the prosecution's case, and other evidence overwhelmingly demonstrated Aesoph's guilt.

The state believes Aesoph is not entitled to a new trial, Long said.