Thursday, October 30, 2003

Is It Laci Peterson's Hair?

The preliminary hearing in the Laci Peterson murder trial is underway. According to a Reuters story, defense counsel spent Thursday trying to exclude testimony from Constance Fisher, an FBI forensic scientist, about a single strand of hair found on a pair of pliers in Scott Peterson's boat. The defense lawyers say that the mitochondrial DNA testing that Fisher employed is less reliable than nuclear DNA tests. They also argue that Fisher should have compared the hair sample to DNA from Laci Peterson's body, instead of with a hair sample from Laci Peterson's mother. Fisher says the test is reliable and the sample was appropriate.

Is this just another example of clever lawyers launching desperate and sophistical attacks on DNA evidence during high-profile trials in California courtrooms? The Denver District Attorney's office has collected a number of judicial decisions on the admissibility of mitochondrial DNA tests.

Update: Here's the LA Times story. Meanwhile, a reader has written to ask a procedural question about admissibility proceedings in California preliminary hearings. Any takers?

posted by pn at 5:51 PM  

Fed. R. Evid. 702: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.