It began as an almost imperceptible trickle.
Across the country, veteran police officers who joined big city departments during the law enforcement hiring boom of the 1970s started creeping up on retirement in the past decade. In Baltimore, it couldn't have happened at a worse time.
Tight budgets had restricted the city's ability to hire officers on a regular basis, and the Baltimore Police Department had become increasingly top-heavy with senior officers - just as the city was enduring one of the longest stretches of violent crime in its history.
Then came Thomas C. Frazier.
Hired as the city's police commissioner in 1994, Frazier arrived in Baltimore after a distinguished career in the San Jose, Calif., police department and instituted the drastic policy shift of rotating veteran officers out of plum assignments to make room for younger officers, women and minorities. No one was spared, not even the detectives in the elite homicide unit.
At the time, Frazier said he was willing to "take some losses" in the number of killings solved by the fledgling investigators as they gained on-the-job training. But over the next six years, records show, the homicide squad took huge losses as veteran investigators left the department rather than return to patrol cars.
So many of them departed that one former detective now says: "I went to more retirement parties in one year than I have in my entire career."
And the rate at which the new detectives solved cases with the arrest of a suspect fell from 68 percent to 40 percent. At the squad's lowest ebb - shortly before the arrival of Commissioner Edward T. Norris in April 2000 - investigators had made 13 arrests in a horrific spate of 80 killings in Northeast Baltimore.
Norris now calls the rotation policy "a disaster for the city and the department" that resulted in hundreds of unsolved murders. Former Commissioner Frazier, now a private consultant to police departments nationwide, declined to comment.
But former Mayor Kurt L. Schmoke, who hired Frazier and supported rotation, said it was partly born of desperation to do something about the city's seemingly intractable murder rate - widely considered to be a driving force behind the devastating exodus of some 100,000 residents from the city in the past 10 years.
"Given that homicide numbers were going down in major cities nationwide, while ours remained very high and static, he [Frazier] felt that we needed fresh blood in the homicide unit," Schmoke recalls. "You have to remember that the numbers were no different in the five years before Commissioner Frazier arrived - when all the old guys were still in the division - than they have been since he left.
"Commissioner Norris is to be commended for finally bringing them down somewhat, but the total number of 262 homicides last year still makes Baltimore one of the deadliest cities in the country. ... We still have a very long way to go before the historical trend is broken."
Other assessments of Frazier's rotation policy have been less forgiving.
According to a confidential department audit ordered by the administration of Mayor Martin O'Malley and since obtained by The Sun, the policy triggered catastrophic declines in morale, training and overall expertise in the homicide unit during the 1990s.
Among other problems noted by Lt. Stephen B. Tabeling, a retired supervisor of the unit and a legendary homicide investigator of the 1970s: "deficient skill levels in the basic investigative aptitudes," "case folders ... in abysmal condition - that is, when they can be located," and "a serious lack of discipline pervading the unit."
"Current practices," Tabeling concluded in January 2000, "verge on the chaotic."
Two years later, an investigation by The Sun has found that nearly half of all homicide defendants are set free or serve minor jail terms on reduced charges because of poor quality investigations and insufficient evidence.