D.C. police Officer Joseph Jennifer didn't leave D.C. Superior Court the same way he arrived. On Wednesday, the 13-year veteran of the force entered Courtroom 212 through the front door. When last seen that day, Jennifer, 38, was being escorted by a U.S. marshal through a side door near the judge's bench. He'd been found guilty of possession of the illegal and dangerous drug phencyclidine, or PCP. Jennifer's destination? A cell at the D.C. jail.

For that conviction, the family of the late Dawn Rothwell and all law-abiding citizens of the District can thank the honorable Craig Iscoe, an associate Superior Court judge who recognized Jennifer as a public danger that the government was too blind to see. More on that at the end.

Joseph Jennifer and Dawn Rothwell have appeared in this column before ["How Did Dawn Rothwell Die?," op-ed, Jan. 25, 2003; "How Did Dawn Rothwell Die? (Cont'd)," op-ed, Feb. 21, 2004]. It still isn't clear how and why Dawn plunged 12 stories to her death in the early morning hours of July 7, 2002. In January 2003, six months after the fall, the D.C. medical examiner ruled her death an accident. Today that decision warrants a hard second look.

The evening before her life ended, Dawn and a longtime friend, Teresa Cole, met up with Sylvester "Ves" Webb, a mutual friend who worked as a barber at a salon on Indian Head Highway in Maryland. Jennifer was with Webb.

Testimony in this week's trial confirmed the essence of February's column: that with Jennifer behind the wheel of his truck, Cole in the passenger seat beside him, and Dawn and Webb sitting behind them, the four drove to Yuma Street SE to buy a "dipper," or a cigarette dipped in PCP.

When they reached the Yuma Street area, Dawn asked for help in buying the dipper. Jennifer gave Cole $20, which Cole gave to Dawn, who went to buy the dipper. The transaction could be seen from Jennifer's truck.

The four of them returned to Dawn's 12th-floor apartment at 800 Southern Ave. SE, where Dawn and her friends, Cole and Webb, smoked the dipper with Jennifer looking on. Jennifer's goal in returning to the apartment was "to get his freak on," or to "have sex" with one of the women, as he reportedly told a homicide detective investigating Dawn's death. Jennifer believed the PCP would assist in that.

Jennifer's attorney, former D.C. homicide chief W. Louis Hennessy, acknowledged during his closing argument that Jennifer was present "while people smoke[d] this PCP" and had made a "serious error in judgment." Hennessy said that didn't mean that Jennifer aided, abetted or assisted them in getting PCP -- to which Iscoe could have said, "Humbug" or some such comment. He didn't.

Instead, Iscoe methodically reviewed the testimony of prosecution and defense witnesses. He found that Jennifer, by driving Dawn and the others to the dealer, by waiting as she got out and purchased the PCP, by contributing money toward its purchase, and by sitting where he could see the transaction take place, was guilty beyond a reasonable doubt of the crime with which he was charged.

Looking Jennifer squarely in the face, Iscoe said he found the police officer's behavior "to be appalling and an appalling breach of trust" when a cop, "who is sworn to uphold the law, has completely abdicated that responsibility and participated in the possession of . . . an illegal and extraordinarily dangerous substance."

But it was the judge's assessment of the defense witnesses, including Jennifer, that bolsters a call for a second look at the medical examiner's ruling in Dawn's death. Webb and Jennifer reportedly were the last two people to be with her the night she died.

Jennifer said he and Cole left Dawn's apartment 45 minutes to an hour after they arrived. Cole said it was longer. Webb reportedly told authorities that he had passed out from intoxication and was in the bedroom when Dawn's fall occurred. Now, consider Iscoe's assessment of the credibility of Webb and Jennifer, expressed in the courtroom, as he announced his decision in the drug case. Let's start with Webb.

The judge noted that Webb had four previous convictions, which reflected on his credibility as a witness. The judge also observed that Webb claimed he had passed out from intoxication, thus avoiding examination by the government on critical issues surrounding the drug purchase.

Iscoe said of Webb: "I found . . . I had some reason to question his credibility on cross-examination. Those reasons increased substantially when Mr. Webb was impeached with, on repeated occasions with testimony from his grand jury appearance sometime earlier."

And this from the judge on Jennifer and Webb: "I did not find the defendant's testimony to be credible. . . . I did not credit the defendant's testimony to the extent it conflicted with other testimony I've described. I did not and I do not credit Mr. Webb's testimony as well." Now to the decision to detain Jennifer in jail until sentencing.

Judge Iscoe asked the prosecutor, Assistant U.S. Attorney Steven Kaufman, for the government's position on holding or releasing Jennifer for trial. "Actually, your honor," Kaufman said, "we will not oppose personal recognizance." The judge reminded the prosecutor that he had to find by clear and convincing evidence that Jennifer was not likely to flee or pose any danger to any other person or to the property of others. "And government, are you submitting that there's no basis for me to make, make that finding?" Iscoe asked. Kaufman then conceded that "[Jennifer] poses a danger."

Iscoe noted that as a result of Jennifer's dangerous behavior, a death resulted. He also observed that Jennifer had been driving while intoxicated and had breached the public trust.

"I'm gonna order him held without bond until the sentencing date."

The judge did his part. When will the government do its part?

Yesterday, Anna Francis, executive assistant to the city's chief medical examiner, called to say that the determination on the manner of death could be changed based on investigative information received from the D.C. police department that warrants and supports a revision.

Still left unanswered: How did Dawn Rothwell die?