Baseball bats used in aggravated assaults. Undergarments worn by rape victims. Knives wielded by the hand of a killer.

This evidence, when tested for DNA, could yield the genetic calling-card of a perpetrator. It could be crucial in proving innocence or guilt.

But in Philadelphia, vital DNA evidence is in jeopardy.

For years, the Police Department has been storing "rape kits," blood-streaked weapons, and clothing from homicide victims in two evidence rooms in City Hall with leaky ceilings and no temperature controls. Over time, DNA degrades if exposed to heat or moisture.

To correct the problem, the city plans to spend nearly $1 million on a state-of-the-art, temperature-controlled evidence room capable of preserving DNA for years.

"I'm glad they are being aggressive and proactive in protecting this important evidence," said Carol E. Tracy, executive director of the Women's Law Project, which advocates on behalf of rape victims. "The cops get an A-plus on this."

Police and city officials said they know of no criminal cases jeopardized by damaged evidence, but they recognize the importance of safeguarding DNA in today's era of forensic science.

Last week, Jerry Miller of Chicago, who served 25 years in prison for a rape he didn't commit, became the 200th person in the United States exonerated by DNA evidence.

Improved methods of extracting DNA not only can exonerate the wrongfully convicted, but can help solve cold cases.

"Technology is always changing," said Joseph Szarka, manager of the city's forensic lab. "With more sensitive technologies, if we didn't get anything the first time, or we only got a partial [DNA] profile, maybe we can go back and get something."

Philadelphia's police force is one of the few in the country that analyzes the evidence collected in all rape kits for possible DNA traces. The kits, put together at the hospital, contain undergarments and swabs taken from the victim's body.

The forensic lab at 8th Street near Poplar analyzes about 1,000 rape kits each year, said lab director Thomas A. Banford.

Once processed for DNA at the lab, the kits go into storage in Room 900 in City Hall.

The lab also tests baseball bats, knives, brass knuckles, and other weapons used in aggravated assaults and homicides. Because of a backlog, however, some of this evidence is stored in another room in City Hall - Room 800 - until the lab's staff can get to it, Szarka said.

Problem is, the environment in both of those rooms is hazardous to DNA.

Rooms 800 and 900 are on the upper, attic-like floors of City Hall and get suffocatingly hot in the summer because there is no air-conditioning. On rainy days, the ceilings leak. Plaster has crumbled from the walls, dusting boxes of evidence, city officials said.

"[The rooms] are really in bad condition because they are under the roof and the roof is leaking," said Richard Tustin, director of the city's Capital Program Office. "We decided that we have to move that stuff out of there."

Tustin added, "Without proper heating and cooling, police have told me the evidence has a potential of deteriorating over time . . . It could have an effect on the readings of the rape kits and everything else."

The new storage location, slated for Room 926, will include stacked shelving, humidity controls, fire alarms and sprinklers, and a high-tech security system. Construction bids are due May 6 and work should take about six months, Tustin said.

"It's going to have all the environmental controls that a room like that should have," Tustin said. *