A former counselor at a Southeast Washington high school was convicted yesterday of sexually assaulting one student and assaulting another.

Tried twice before on sex crime charges, John T. Jones had never been convicted -- until yesterday, when a jury in D.C. Superior Court found him guilty of seven counts of misdemeanor sexual abuse and other offenses.

Defense attorneys had argued that Jones's job as the attendance chief at Ballou Senior High School made him a target, and they portrayed the accusers as lying, vindictive students.

But the jurors found that he had sex or other sexual contact repeatedly with the girl who was the principal accuser and that his "significant relationship" with her made the activity even more criminal. The incidents occurred from 2001 to 2003.

The jury convicted Jones, 39, of assaulting a second girl but acquitted him of sexually enticing her. The jury also acquitted Jones of assaulting a third student.

While the guilty verdicts were a welcome victory for prosecutors, the jurors convicted Jones only of misdemeanors. That means he will face several years in prison, much less than if had he had been convicted of felonies. Jones, a Ballou alumnus, has been jailed since his arrest in May 2003. His sentencing was scheduled for Aug. 27, and he will be required to register as a sex offender in the District.

The jury forewoman, a 54-year-old accountant, said afterward that the jurors were "absolutely" certain that Jones had assaulted the main accuser but were not certain that any encounters took place before she turned 16, which would have made the crimes felonies.

Many of the incidents were said to have occurred on unspecified days during stretches of as long as several months -- a gap in the case that prosecutors tried to explain. Jones, they said, preyed on the main victim's vulnerabilities as a foster child, "grooming" her to the point that she simply went along with what she thought was inevitable, hardly bothering to keep track of times and dates.

Ultimately, that explanation was enough to sustain the overall credibility of the girl, in spite of the defense's aggressive attempts to exploit inconsistencies in her accounts and those of the other two accusers.

Prosecutors say that cases of sexual assault involving adolescent girls, who are often reluctant to come forward, are among the hardest to win. In this instance, it took two trials.

In March, a jury acquitted Jones of several charges but was unable to return a verdict on numerous others. Prosecutors decided to try the case again on the remaining charges. Seven years earlier, in a different case, the U.S. attorney's office did not retry Jones after a jury deadlocked on charges that he had raped a 15-year-old girl.

This time, Assistant U.S. Attorneys Cynthia G. Wright and Geoffrey A. Barrow were able to introduce a couple of important witnesses who did not testify when the current case was first heard in March.

One of those witnesses was the woman from the case in 1997 that ended up with a hung jury. Judge Ann O'Regan Keary limited the scope of her testimony and what prosecutors could argue based on it, but it gave jurors an additional perspective.

John T. Jones escaped conviction in two other trials on sex charges.