In the Michigan Case of People V

In the Michigan case of People v. Thomas, the defendant had been accused of beating his wife and her boyfriend to death. A former inmate, who had served time with the defendant and who regularly conversed with defendant while they were incarcerated together in a county jail, testified that defendant confessed that he had killed his wife and her boyfriend by beating them with a statue. The former inmate had the wrong name for the defendant's wife, and the murder weapon was a board with nails protruding. The defendant alleged that the former inmate's testimony was so inherently incredible that the record showed that the former inmate did not have the capacity and sense of obligation to testify truthfully. Thomas argued that he should get a new trial based on the alleged incompetent testimony. The appellate court found that:

A) when a witness gives an incorrect name for a murder victim and when he alleged that he had spoken to the defendant who confessed to the former inmate, the witness does not have sufficient capacity to testify about the case.
B) when any witness testifies to obviously incorrect facts [name of victim and method of death], the witness is not competent to testify and a new trial is required under such circumstances.
C) the former inmate's testimony indicated that he possessed competency to testify, even though he had incorrectly identified the name of the defendant's wife and incorrectly described the weapon. The defendant failed to rebut the presumption of competency that every witness has.
D) a witness is always competent to testify and that errors only relate to the weight to be given the testimony. No new trial was ordered.