An Arlington County judge reinstated a $40,000 bond yesterday on Michael Charles Satcher after his attorney argued that results of forensic tests should remove Satcher as a suspect in the bike trail slaying last spring of a young Arlington woman.

Satcher, charged 10 days ago with assault in attacks on two women on a county bike trail, was denied bond last week after blood tests revealed a strong similarity between Satcher and the person who killed paralegal Anne Elizabeth Borghesani, 23, five months ago, according to prosecutors. Borghesani's body was discovered near another Arlington bike path. She had been stabbed repeatedly, police said.

More recent tests revealed that hair samples taken from Borghesani's body did not match Satcher's, according to court testimony.

Although the hair samples are different from Satcher's, Deputy Commonwealth's Attorney Richard E. Trodden said after the hearing that Satcher "is still very much a suspect" in the Borghesani case, pending the results of DNA tests from the state forensic lab in Richmond. Prosecutors said the results from the DNA tests are not due for several days.

Trodden did not object to the motion to reinstate Satcher's bond.

Police have not charged Satcher in the killing. He was still being held in the Arlington County Jail last night.

Yesterday's hearing demonstrates the growing importance of highly technical -- and sometimes contradictory -- forensic evidence.

Police took hair, saliva and blood samples from Satcher for testing after his arrest. They were compared with samples taken from Borghesani's body and the site where she was found.

When blood test results released last week indicated that Satcher and the man who killed Borghesani share a blood type found in only seven out of 100 people, Arlington prosecutors announced that they finally had a suspect in a murder case that had produced few leads.

On Friday, further tests at the Northern Virginia Forensic Laboratory revealed that comparisons between Satcher's hair and body hairs found at the scene of the Borghesani slaying appear to rule him out as her assailant.

Satcher, 22, a Washington man, was charged on Aug. 18 with attacking two women on an Arlington recreation trail after police found him following a third woman with a knife concealed in his shirt, police said.

Similarities between the two recent assaults and the fatal attack five months ago led police to investigate Satcher in the Borghesani case as well.

The best that blood or hair sample testing can do, experts agree, is to allow an investigator to rule out an individual as a suspect.

"Just as you wouldn't convict based on the 7 percent, you wouldn't say that the hair evidence will acquit him," said James Starrs, professor of forensic science and law at George Washington University.

"Hair and blood cannot be specifically identified with an individual like a person to a fingerprint or a bullet to a gun," said Charles Killian, regional director of the Northern Virginia Forensic Laboratory in Fairfax.

Hair samples can determine a suspect's race and hair texture, Killian said. And scientists can compare a suspect's blood type, as well as the pattern of proteins, enzymes and other markers, to samples taken from a crime scene.

Only fingerprinting and DNA testing can provide evidence that can be used to pinpoint a suspect, experts say.

DNA, or deoxyribonucleic acid, is the basic genetic material found in cells of every living organism. Scientists believe that every individual, with the exception of identical twins, has a unique DNA fingerprint.

Investigators say that by analyzing microscopic patterns in the DNA of bodily fluids or tissue left at a crime scene, they can determine conclusively whether an individual was there. Frequently the evidence is considered so strong that it convicts or exonerates a suspect all by itself.

DNA testing has won wide approval in Virginia, which was the first state to use it. Beginning last month, convicted felons throughout the state were required to submit to blood testing for a statewide DNA data bank.

The naming of a suspect in the Borghesani case has reopened old wounds for the young woman's family and friends.

"None of us wants to relive this," said Dana Carver, a close friend and former classmate from Tufts University, where Borghesani graduated in June 1989 and where a scholarship has been set up in her name.

"Friends of the family and friends of Ann's have given about $35,000," said Kathy Reid, of the university development office. "They've gathered around to do something that will honor her memory."