DNA on Trial

Now, let me see if I have this straight: On the one hand, the Simpson defense team is claiming that the police took a vial of O.J.’s blood and sprinkled it all over the crime scene to incriminate him. On the other hand, they’re claiming that the DNA testing on those same samples was so contaminated that the results cannot be trusted to prove it was O.J.’s blood.

It’s me, right?

GUS BRO

Santa Barbara

* If you think that the odds are high against someone other than O.J. spilling his blood on the same night at the Bundy murder scene and in his home, consider what the odds are in the defense scenario of a non-O.J. murderer’s blood being so contaminated that it randomly picks up the same DNA code as the murdered woman’s husband.

JIM HARRIGAN

Manhattan Beach

* Blood is thicker than hypothesis.

AL ALU

Los Angeles

* If it is a fact that one person in 170 million has a DNA fingerprint that matches the blood drop found at the scene and that it also matches Simpson’s DNA fingerprint, we should be careful not to conclude, as the DNA expert has, that the probability of the blood not being Simpson’s is 1 in 170 million. This probability depends on a lot more than the DNA’s uniqueness. If only one person in 170 million has this type, this means that there are approximately 30 people in the world that have this type of blood. So the probability that the drop is not Simpson’s depends upon the likelihood that one or more of those other 29 people were in Brentwood that day. This is not the kind of judgment that a DNA expert is qualified to make.

WILLIAM TOMLINSON

Frazier Park