San Diego

The judge in the murder trial of Mark Radke will rule today whether an expert in “blood stain interpretation” will be allowed to testify about his opinion that two people were involved in the murder of 16-year-old Jeffrey Rudiger.

The testimony of detective Brian Kennedy, a Sacramento County sheriff’s deputy, is the only evidence supporting contentions made in opening statements by Deputy Dist. Atty. Daniel G. Lamborn that Radke, 24, had an accomplice in Rudiger’s murder on the night of Jan. 21, 1988.

Kennedy, who is the last prosecution witness in the San Diego Superior Court trial, began his testimony Thursday afternoon, but he was cut short by objections from defense attorney Douglas C. Brown. After a hearing with the judge, Brown said Kennedy’s testimony was “conjectural, speculative, and should be excluded.”

Other testimony was given Thursday by Brian Wraxall, a forensic serologist, who tested blood recovered from Radke’s car.

By testing two genetic markers, Wraxall said, it was determined that the blood found under two of the wheel wells could have belonged to Rudiger but did not belong to Radke.

Combining his data with testimony delivered by another expert yesterday, Wraxall said the blood sample matched Rudiger’s and only .044%--or one person out of 2,272--of the Caucasian population has the same kind of blood.