He said he notified Police Commissioner Frederick H. Bealefeld III when the oversight was discovered. He said Bealefeld was "not happy" and told him to resign late Tuesday.
"I was there 12 years and never had any issues," Koch said, adding that he was never informed of any other concerns with his job performance. "That's good personnel in there, and they should not be knocked for everything. I think [the criticism] is blown out of proportion."
Several experts, including the director of the national crime lab accreditation board, said they were surprised that Baltimore had failed to take what they called the basic step of cataloging the employees' DNA.
"It's a uniformly standard practice of laboratories doing DNA testing," said Ralph Keaton, director of the American Society of Crime Laboratory Directors/Laboratory Accreditation Board. That board accredited Baltimore's lab in December 2006.
Keaton said that maintaining an employee database is not a requirement of accreditation but that not doing so is all but unheard of. After learning about Baltimore's contamination from reporters and a public defender yesterday, Keaton said he would call the Police Department to follow up but did not say whether the lab's accreditation could be at risk.
Two local agencies, the Maryland State Police and the Baltimore County Police, said they have always maintained DNA databases of laboratory employees who come into contact with the samples. Police spokesman Bill Toohey said that since Baltimore County began testing DNA in 2001, the first step in any analysis has always been to test samples against the staff profiles.
Clifford stressed that the contamination "didn't produce false positives," meaning that no suspects were inadvertently identified because of the lab's mistakes. He said the city crime lab and its DNA section were fully operational yesterday.
"Fewer than 15 known incidents of staff contamination over seven years isn't the kind of thing that holds up lab operations," Clifford said.
But Patrick Kent, chief of the forensics division at the state public defender's office, said police are "talking out of both sides of their mouth."
"They're saying, 'Oh, it's not a problem at all,' and on the other hand they have fired the crime lab director," Kent said. "And I can tell you that never happens. Crime lab directors are only fired when you have some serious quality control violations."
