Saliva helps police finger a suspect

January 31, 1993|By Kris Antonelli | Kris Antonelli,Staff Writer

All Bill Vosburgh had to go on was a small amount of saliva the killer left on the rim of a soda bottle.

"There was really no physical evidence to speak of," said Mr. Vosburgh, a chemist in the Anne Arundel County police crime lab. "But the Coke bottle was on the table, and the children said their mother never drank [Coca-Cola]. It was just kept in the house for guests."

A few months later, that saliva left on the bottle, combined with a relatively new DNA test called Polymerase Chain Reaction (PCR), led homicide investigators to Albert G. Givens. The Annapolis man was charged with first-degree murder in the slaying of Marlene Kilpatrick of Arnold.

Mr. Givens' trial, which begins March 4 in Circuit Court in Annapolis, will be the first test of the proce dure in the state, police and prosecutors believe. During a hearing, Judge Raymond G. Thieme Jr. will determine whether the results will be allowed as evidence.

Thirty-six states have approved the procedure, Mr. Vosburgh said.

Explained simply, the test works like this: Investigators take a blood, saliva or other bodily fluid sample and bring it to the lab. Mr. Vosburgh puts the sample through a machine called a Thermal Cycler, which makes millions of copies of the DNA genetic pattern. He then takes that sample and compares it to genetic patterns found in a suspect's blood.

"The advantage of this is that a tiny amount of evidence or bodily fluid can generate a result or match," he said.

Mr. Vosburgh said a standard DNA test requires a larger sample of bodily fluid, enough to cover an area the size of a quarter. But since the PCR process copies a sample, it's especially valuable in crimes in which only a small amount of fluid has been left behind.

While police and prosecutors favor DNA tests, including the PCR process, defense attorneys question their reliability. Since the amount of the sample being tested is smaller in the PCR process, the odds are that one in 25 people have the same genetic marker.

The odds in a standard DNA test are typically in the millions, Mr. Vosburgh said, making that type of test more accurate.

Paul Kirby, Mr. Givens' attorney, said he planned on having some experts testify against the test. Mrs. Kilpatrick, 56, was found dead with a knife in her chest in the bedroom of her home in the 100 block of Church Road about noon Jan. 3, 1992. Police believe that the killing took place between 11 p.m. Jan. 1 and the morning of Jan. 3.

From the start, investigators thought that Mrs. Kilpatrick knew .. her attacker. They collected blood, hair and saliva samples from 16 suspects, including Mr. Givens, a handyman who did work around her house. Mr. Vosburgh used another test to determine that the person who left the saliva on the bottle had Type A Blood. He sent the bottle and five suspects' samples -- all Type A -- to a private company in Germantown to perform the PCR test.

Beginning in July, Mr, Vosburgh will be able to perform the test himself, in the lab behind police headquarters in Millersville.

It cost Anne Arundel County Police about $25,000 to buy the equipment and train Mr. Vosburgh. But he says the cost of sending out samples for processing costs $350, and he estimates he'll be doing as many as 500 tests a year.

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