The crime rampage that George Haynes allegedly embarked on after being paroled from prison last fall was strictly low-tech -- just your basic grab-and-go stickups, much like a spate of robberies in 1997 that landed him behind bars for seven years.

Here's the difference, though: While Haynes was locked up, modern technology kept advancing. And what led to his arrest this time, in armed robberies at four D.C. hotels, was an electronic trail that he might not have realized he was leaving, police said.

For nearly a year, D.C. police were confounded by a prolific holdup man whom they could neither identify nor catch. From October until last month, they counted 24 robberies at Northwest Washington hotels that they believed were linked, all committed by someone described by victims as a slender, black male taller than six feet who wore a mask.

Sometimes the robber got away with a few hundred dollars, but often less.

While detectives searched for the robber, Haynes, now 24, was on parole and living in Prince George's County, according to the Court Services and Offender Supervision Agency, which monitors D.C. parolees.

From October to June, Haynes -- 6-foot-3 and 170 pounds -- was under "medium supervision," said Leonard E. Sipes, the agency's spokesman. But because of several "technical violations" of his parole conditions, Haynes was put under stricter supervision June 20, Sipes said. He was not allowed out of his home from 5 p.m. to 5 a.m.

To monitor Haynes's whereabouts, Sipes said, the agency fitted him with an electronic ankle bracelet and required him to carry a transmitter on his belt during the day.

The transmitter contained a Global Positioning System that tracked Haynes's movements during the day. At night, he put the transmitter in a home docking station, and Court Services downloaded a block-by-block record of his travels. An electronic signal between the ankle bracelet and the transmitter prevented Haynes from secretly going somewhere without the GPS device. If he had done so, the violation would have been noted in the downloaded data.

Through the summer, the holdups continued at high-end hotels.

July 24, at 8:15 a.m.: Three people were robbed of $502 at gunpoint in the garage of the Wardman Park Marriott in the 2600 block of Woodley Road NW.

Aug. 2, at 9:55 a.m.: An armed man took $400 from two people in the garage of the Carlyle Suites Hotel in the 1700 block of New Hampshire Avenue NW.

Aug. 7, at 6:15 a.m.: A person standing in front of the Topaz Hotel, in the 1700 block of N Street NW, was robbed of $103 at gunpoint.

Sipes said that Haynes remained under electronic supervision until Aug. 13, when he allegedly cut off his ankle bracelet and stopped reporting to Court Services. He no longer was abiding by his 5 p.m. curfew, Sipes said. A warrant was issued for his arrest as an alleged parole violator, Sipes said, but authorities could not locate him.

Aug 25, at 10:35 p.m.: Three people in the garage of the Savoy Suites, in the 2500 block of Wisconsin Avenue NW, were robbed of $40 and three cell phones.

The cell phones were a break for police. On Sept. 15, they obtained calling records and saw that one of the phones had been used repeatedly in the hours after the holdup and that a number listed to a woman on U Street NW had been called. Detectives visited the woman, according to a court affidavit. "During the interview, [she] was queried as to whether or not she knew anyone fitting the description" of the elusive robber, the affidavit says.

She "related that her son fit the description and provided his name of George Haynes."

The rest was little more than paperwork: A records check showed that Haynes was a parolee, and Court Services gave detectives a log of his travels while he was carrying the transmitter and sticking to his curfew. The log put Haynes on the blocks where the morning holdups occurred July 24, Aug. 2 and Aug. 7, the affidavit says.

Arlington County police said yesterday that they obtained an arrest warrant charging Haynes in a July 16 hotel robbery there and that he is a suspect in eight similar holdups in Arlington.

Besides being charged in the three D.C. robberies to which he was linked by the GPS device and the holdup involving the cell phones, police said, Haynes was charged in an April 25 robbery in the Savoy Suites garage in which $40 and a Kenneth Cole watch were stolen. That was before Haynes had an ankle bracelet and a transmitter.

The watch turned up in a D.C. pawnshop, according to the affidavit. As for the man who sold it, the affidavit says, "He identified himself as George Haynes . . . to the pawn broker."

Staff writer Henri E. Cauvin contributed to this report.