Two District men accused in a series of armed rapes and robberies since August and arrested Wednesday at their Northwest Washington homes, were held without bond yesterday to await trial in D.C. Superior Court.

The serial assaults, part of a dramatic upswing in sexual offenses this year in the District, were known among police investigators as the "Mutt and Jeff" rapes because police sought two men -- one tall, one very short -- whom victims described as following a consistent pattern of attack.

In six incidents, all taking place between midnight and 2 a.m., young women walking alone or in groups of two or three in Northeast and Southeast Washington reported being abducted by two men at the point of a silver-colored handgun in a new blue-gray car. The victims were taken to St. John's College High School at 2607 Military Rd. NW, to 6210 Chillum Pl. NE, or to the 3300 block of Quesada Street NW behind Lafayette School, where they were robbed or attacked.

In five of the incidents, the women abducted told police they were robbed of their cash and jewelry and ordered to remove all their clothes, after which some of the women were forced to have intercourse and oral sex with the two men. In the sixth incident, three young women were robbed and threatened with rape at the St. John's school.

Darin C. Hagins, 25, of the 5700 block of 14th Street NW, and Lomax V. Hughes, 24, of the 1400 block of Madison Street NW, have been formally charged only with the armed rape of two women on Sept. 20.

But Assistant U.S. Attorney Wanda G. Bryant, brandishing 31 pages of police affidavits, told Hearing Commissioner John W. Treanor yesterday that the government had "clear and convincing evidence" that the men committed the other similar offenses.

Prosecutors ordinarily do not reveal so much about their evidence on the day after arrest, but Bryant wanted to persuade Treanor to jail the two men without bond. Though the District's Bail Reform Act requires pretrial release for most defendants, there is an exception for defendants who have engaged in a "pattern of dangerous crimes."

Treanor ruled that the incidents "add up to a pattern, and there is no condition or set of conditions {of release}, in my opinion, that would ensure the safety of the community."

Hagins, who is less than five feet tall, has been charged in four previous drug or property crime cases, but three of them were dropped by prosecutors. He pleaded guilty in 1989 to attempted burglary and destruction of property. Hughes has no adult arrest record in the District.

Law enforcement sources said that both men spoke extensively to police after their arrest. Hagins "was singing like a bird," according to one source. Another said Hagins "seemed to be enjoying his celebrity status in here."

"They're denying it was rape, but they admit they're the people we were looking for," the second source said.

Ronald Horton, Hagins's lawyer, declined to comment.

Abraham C. Blitzer, who represents Hughes, said his client maintains his innocence and has offered no account of the alleged assaults. "If you're innocent, you don't know anything," Blitzer said. "You're totally in the dark."

Search warrants returned in Superior Court yesterday reported the discovery of a .22 caliber revolver at Hagins's house; a silver handgun, jewelry, and clothing, matching some described by victims, at Hughes's house; and a bulletproof vest, a pair of handcuffs and jewelry from Hughes's blue-gray Hyundai Excel.

The two men, according to a police affidavit, were picked out of separate photo spreads by a 16-year-old victim in the Sept. 20 assault.

The 16-year-old told police she was trying to catch a cab with a 22-year-old friend at the corner of Georgia and Florida avenues NW when two men offered them a ride. The teenager said Hagins put a gun to her head, forced her and her friend into the car, and drove them to Lafayette School.

There both men, she told police, raped her and the woman, and then Hughes forced her to perform oral sex on him. Hughes told her, she said, that if she "dimed" on him that he was going to kill both of them.

"Drop a dime" is street slang for a report to authorities.