A man picked up by police last month after he was spotted apparently following an elderly woman may be partly responsible for as many as 20 armed robberies on and around Capitol Hill between June and August, D.C. police said.

In most of the robberies, a victim walking alone, usually a woman, was forced either to drive or walk to an automated teller machine and withdraw money from a bank account. At least three of the victims also were sexually assaulted, police sources said.

The arrest of the suspect, Neville Antwoine Saxton, is part of a broader inquiry into a spate of robberies on Capitol Hill and in the neighborhood north of Union Station, officials said. The robberies, which could total as many as 30, are being investigated by detectives from the 1st and 5th Police Districts and from the Special Investigations Division.

Police said Saxton was sometimes aided by a 14-year-old accomplice, whose involvement in the robberies is still being determined. The teenager has been arrested, but police declined to provide details because he is a juvenile. Aside from the two, police also have arrested three other suspects in what they believe are unrelated robberies in the same neighborhoods.

But despite the arrests, residents are complaining that not enough was done to inform them about the pattern of crimes. "The police don't do a really good job of alerting the community of what's going on," said Marvin F. Fields Jr., a member of the 6A Advisory Neighborhood Commission, where some of the robberies occurred.

First District Cmdr. Kim C. Dine said the district has seen a 60 percent overall decrease in robberies since 1996 and said the recent string is an aberration. "One robbery's too many, that's a given," Dine said. "But I think this was a case where . . . we did a very good job of analyzing the problem, trying to get the word out and make a number of arrests that successfully closed a number of these cases."

Saxton, of the 1400 block of Staples Street NE, was arrested in the early morning of Aug. 24 after a 1st District police officer saw him following the elderly woman in the 200 block of Sixth Street SE, police said. With the officer, Kenneth Catterton, in pursuit, Saxton fled on foot and fired a handgun before being caught on nearby North Carolina Avenue SE.

Saxton, who turns 26 on Sunday, was charged with carrying an unlicensed pistol. After detectives questioned him, Saxton also was charged with the Aug. 16 armed kidnapping of a woman who was abducted after leaving her car in the 600 block of A Street NE, police said. That victim was forced to withdraw $800 from a Crestar Bank ATM at 500 Morse St. NE. Saxton allegedly fled after trying to force the woman to take out more money from a Bank of America ATM at Third Street and Florida Avenue NE.

Three days after the arrest, police obtained a warrant charging Saxton with first-degree sexual abuse, armed kidnapping and armed robbery in an Aug. 1 attack. That victim was threatened with a handgun while using a pay telephone and was forced to drive to and withdraw cash from a Citibank ATM at 12th and Perry streets NE. The victim was then raped in her own car, according to the arrest warrant.

Two of the three charges are now before a D.C. Superior Court grand jury. Saxton is scheduled to appear in court Tuesday in the Aug. 1 attack, according to Channing D. Phillips, a spokesman for the U.S. attorney's office.

D.C. police detectives are now investigating whether Saxton and the 14-year-old accomplice may be linked to as many as 20 similar crimes. "We are backtracking six months' worth of cases that have similar MOs and physical descriptions," said 5th District Detective Vincent T. Spriggs Sr., referring to the robber's method of operating, as described by the victims.

One of the victims is Sharon A. Isch, a 62-year-old retired promotional copywriter for The Washington Post. Isch said she was accosted the night of July 15 when she was about to enter her house in the 600 block of Pickford Place NE. She was then forced to drive to three ATMs and withdraw money at each. The man followed her to each machine and stayed within arm's reach, Isch said.

"Twice when getting out of the car and [when] my back was to him I silently mouthed 'Help me' to men passing by but got no reaction," Isch said. She said her hour-long ordeal ended when the man fled with her money and some jewelry.

Detectives confirmed Isch's account and said hers is one of several additional cases that may be linked to Saxton.

D.C. Superior Court records indicate that Saxton pleaded guilty in April to a traffic violation and was sentenced to one year of probation. In Maryland, Saxton also had been charged last year with second-degree assault and in 1992 with robbery with a deadly weapon, assault with intent to rob and a handgun violation, according to court records there. The outcome of those cases could not be determined.

The Bank of America ATM at Third and Florida links several of the cases. Aside from the robbery on Aug. 16, two other women were abducted and forced to withdraw money there July 22 and 27, police said. The victims in both of those cases also were sexually assaulted.

Herbert J. Amons Sr., another 6A Advisory Neighborhood Commissioner, said that "there hasn't been a great deal of publicity" about the robberies. But Amons also said "people have got to look out for themselves."

Fields, the other ANC commissioner, said monthly meetings with police are the only opportunity for residents to learn of crime patterns. "There should be another mechanism to make people alert about what's going on so people can be more conscientious about [not] being crime victims," he said.

Capt. Alan Dreher said 1st District police sent several e-mail messages about the robberies to Capitol Hill residents, in addition to posting fliers and issuing two news releases. It took time for investigators to discern the pattern, he said, adding that the bottom line is that the police inquiry is largely concluded.

"The [robberies] that involve abductions or ATM issues, we've arrested the perpetrators," Dreher said. "Since the arrests we haven't noted any additional cases."

Staff writer Peter Slevin and Metro researcher Bobbye Pratt contributed to this report.

CAPTION: On her way to a party downtown, a Gaithersburg woman stopped at Third and Florida NE to use the ATM because it was well lighted and "seemed safe."