An Alexandria detective playing every longshot to solve three similar slatings, placed a call on May 5 to Fairfax County investigators that led to what police now believe is the solution to the slaying of five young women in Northern Virginia.

Capt. Clyde Scott, chief of Alexandria's criminal investigation division, said the detective called Fairfax police to see if he could link the three apparently connected Alexandria slayings with the March 6 murder of a 22-year-old woman in Fairfax.

In response to that call, Fairfax County police sent sets of fingerprints to Alexandria that had been taken from the car of Ursula A. Miltenberger. She had been found stabbed to death in Western Fairfax, but police had been unable to identify the fingerprints on her car from records in their own or national files.

One set of the fingerprints, Scott said, matched the prints of 18-year-old high school, droupout Montie Ralph Rissell, who has since been charged with the Miltenberger slaying and named by police as their suspect in the other four slayings.

The Rissell fingerprints were on file at the Alexandria police station and nowhere else, Scott said, because they were taken when he was arrested as a juvenile in the city and not been entered in national criminal files.

When the prints from Miltenberger's car were matched to those of Rissell, police said, the young man immediately became the focus of the slaying investigation. He lived near the other victims in the high-rise apartment district of West End Alexandria and his juvenile record included a 1973 rape and a 1975 attempted robbery.

In the attempt, he was accused of confronting a young woman with a knife as she stepped off an Alexandria apartment elevator. The woman escaped unharmed.

By chance, the Alexandria detective - whom Scott declined to identify - whose initiative linked Rissell to the Miltenberger car had dealt with Rissell as a juvenile offender.

The fingerprints alone were not enough to trigger an arrest of the young suspect. A souce in the investigation said Rissell had worked at a service station where Miltenberger was believe to have taken her car for servicing. The station, the source said, is close to the McDonald's Restaurant in Alexandria where Miltenberger was a management trainee.

That fact, however, did not put police off Rissell's trail, the source said. Another piece of evidence - a key among Miltenberger's possessions - indicated she may have had access to an apartment near Rissell's home and in the same area where the other victims lived.

From the time of the fingerprint matchup, Scott said, Fairfax and Alexandria officers maintained a joint "shotgun stakeout" on Rissell around the clock. Officers armed with shotguns followed his evey move.

The 5-foot-8 inch tall young man who lived nearby was such a familiar figure to other residents of the Holmes Run Park Apartments that he moved about the building freely without attracting attention, Scott said, even during the peak period of tenant fear that followed the discovery of the first three bodies.

A source said Rissell even was seen riding in a car with a female assistant apartment manager in the area making night security checks. Unknown to both Rissell and the manager, police were watching him during these rides.

Still lacking the evidence they felt they needed, police finally questioned Rissell on May 13 about the murders. He was kept in custody by Fairfax police, who charged him with malicious wounding at a party brawl last month that was not connected with the slayings.

Then, on Tuesday, police found the badly decomposed body of Aletha Byrd, 35, in a wooded area across 1-95 from the Holmes Run Park Apartments where she had lived. Byrd had been missing since April 10.

On the same day, according to anaffidavit in support of a search warrant filed in Alexandria Circuit Court, police searched a car belonging to Roberta Hindrey, Rissell's mother in response to a tip.

Investigator Richard C. Appleton said in the affidavit tha Mrs. Hindrey, her oldest son, Horald Rissell and a station employee said the car was towed to the Lincolnia area near western Alexandria from a Maryland service station. It had become disabled three or four weeks earlier while Montie Rissell was driving it on the Capital Beltway, the affidavit said.

Appleton said in the affidavit that Mrs. Hindrey gave officers written permission to search the car and when they did they found shoes, a wallet and other personal belongings of Byrd.

Appleton said that in the trunk of the car they found a wallet with Byrd's driver's license sticking out of it. The wallet also contained credit cards belonging to Bryd, he said.

The officers spotted a key case in the trunk that matched descriptions of a case that friends of Byrd said she owned, Appleton said, and a pair of earth shoes, which are shoes with toes higher than the heels.

Inside the car, Appleton said, officers saw a pair of brown gloves, an Afro comb and a knife with a blade "four inches long or more."

On the same day that the car was searched, police said in another affidavit filed Wednesday, officers questioned Montie Rissell and then discovered in his apartment a wristwatch that belonged to Jeanette M. McClelland.

It was the discovery on May 5 of the body of McClelland, 24, another Holmes Run tenant, that convinced police they were investigating a series of connected murders. Prosecutors now say they will seek indictments against Rissell in connection with the slayings of McClelland, Byrd, MIltenberger, Gladys R. Bradley, 27, a Holmes Run Apartments resident whose body was found drowned in a creek on April 30, and Aura Marina Gabor, 26, a Holmes Run resident found dead last August.

Four of the five women found slain since August were stabbed and the fourth apparently was drowned in a creek. Alexandria Commonwealth's Attorney William Cowhig said yesterday that all four stabbing victims had been wounded in almost the same spot in the upper right chest.

Cowhig said he will seek four separate indictments today charging Rissell with murder, rape and abduction of each of the four Alexandria slaying victims.

Fairfax Commonwealth's Attorney Robert F. Horan said Rissell probably will be tried in Alexandria first because the next Fairfax grand jury will not meet until July.

The murders have terrorized Western Alexandria apartment residents and Dreyfuss Brothers, Inc., manager of the Holmes Run Park complex, where three of the victims live, sent a memo to tenants Wednesday saying new security devices would be installed. Installation has begun of quartz lights in parking areas, dead bolt locks on apartment doors, bars on terrace level sliding doors and locks on the side and entrance doors of the elevator buildings. These doors will be locked at night, the memo said.

The management firm also said it will install phone booths on the property so that visitors may call apartments to gain admittance.