Two tiny bottles of an experimental chemical have joined the powders, dyes, scopes and ultraviolet lights that city investigators tote to a murder scene. The chemical -- called RTX -- could revolutionize homicide investigations. Currently, only in the rarest of cases have police found and lifted the fingerprints left on a victim's body. In the lab, RTX can highlight fingerprints left on skin and other porous materials. "That would be such a powerful discovery, to be able to consistently say who touched that person in the heat of passion," said Wayne Reutzel, chief of latent fingerprint identification in the Allegheny County Coroner's forensic lab. "Lifting prints from bodies is really the next leap in fingerprint technology." Pittsburgh police, led by city crime unit Sgt. Paul McComb and with the help of the county coroner's office, have begun experimenting with RTX. Police bought two $250 bottles of the chemical in January from the Japanese chemist who created it. McComb and Reutzel said they are ready to use it in the right case, namely homicides in which police strongly suspect the killer has touched the body. When Noreen Apjok was found half naked, beaten and suffocated in a Lincoln Park picnic shelter in October, police tried to get prints from her body using traditional methods because they did not have RTX at the time. "That's the kind of case we need this for, brutal crimes where the killer may have left behind the only evidence we might get," said deputy city police Chief William Mullen. RTX is short for ruthenium tetroxide, a volatile chemical that adheres to the fatty materials in the oil people secrete from hair follicles. The oil is transferred to the fingers when people touch the hair follicles. RTX was designed and is sold by Kenzoh Mashiko, a retired chemist who worked in Japanese crime labs for more than 30 years In 1997, Mashiko conducted scientific trials that showed RTX liquid or its fumes could highlight fingerprints on skin and other porous materials. "Clinical trials have shown various different methods can work sometimes," said retired Miami crime scene investigator William Sampson, of Tallahassee, Fla., who with his wife Karen has published several papers on fingerprint recovery. "What needs to be documented is how they work in the field." McComb said he heard of the product through the International Association of Identification, a professional group of forensic investigators, and decided to give it a try. "I touched my arm with my finger, put the RTX on and the print came up," McComb said of his first experience with a sample several months ago. "That showed me at least this was worth a try." Retired city police Cmdr. Ron Freeman and McComb also convinced Dr. Cyril Wecht, the county coroner, to allow investigators to try RTX on dead bodies at the morgue. The RTX worked in some cases, but not in others. They key is to find out why. Reutzel said investigators need to document everything, and to try RTX under many conditions. "Different temperatures and the time between when the print is placed and when it's lifted are going to be important," he said. "And then you need to do it over and over to see if the results are consistent." Sampson said he has found 60 cases in the past 30 years in which investigators got prints from a body. RTX was not used in any of them, but several similar chemicals have worked in 11 cases. Sampson said that in all but four of the 60 cases he has documented, the prints were lifted under controlled conditions, usually at the morgue or in a lab.

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