DURHAM, N.C. — How do you make 16 jurors smile in unison? Tell them they don't have to come back to court for a week. That's what happened Wednesday when Judge Orlando Hudson Jr. announced that because of unspecified scheduling issues, there will be no further testimony at novelist Michael Peterson's first-degree murder trial until Wednesday Aug. 6.

There have been 21 days of testimony so far and jurors have heard from 30 prosecution witnesses. At this pace, however, the trial will probably extend well into September and could even spill over into October; the first juror was selected in early May. Before the jury was sent home Wednesday, they heard from two special agents from the North Carolina State Bureau of Investigation (SBI). The first, DNA expert Mark Boodee, testified that saliva he detected on a Diet Coke can seized by police came from the defendant, Michael Peterson, and that DNA from other unknown individuals was also found on the can.

Police seized the can from the patio area outside the Peterson home on Dec. 9, 2001, the day Peterson called 911 to report finding his wife injured but breathing at the bottom of a flight of stairs. Kathleen Peterson was dead, however, by the time police arrived. As with other evidence, the prosecution did not ask Boodee any questions that would suggest how Michael Peterson drinking from a can of Diet Coke fits in with the state's theory that he killed his wife and staged the scene to look like a fall.

Boodee also testified that all the blood he tested from the stairwell where the body lay was from Kathleen Peterson. SBI agent James Gregory, the only other witness called by the prosecution Wednesday, testified about hairs police collected from several steps in the stairwell. Some of the hairs, which also came from Kathleen Peterson's head, appeared to have been cut or broken.

Prosecutor Freda Black asked if hair follicles can be broken by, say, a head being smashed against a step. Gregory said that could be the case. On cross-examination, however, Gregory agreed with defense lawyer David Rudolf that a hair that breaks free from a scalp during combing might also appear to be forcibly removed.

The witness said that the hair could been cut or yanked out if Kathleen Peterson's head came into contact with sharp edges on a chair lift in the stairwell, although he could not testify that that was the case.

Before sending the jury home, Hudson read a special jury instruction that the defense insisted on over the objections of prosecution. The issue it addressed was the testimony from Durham police crime scene investigator Eric Campen, who said that he had destroyed a diagram of the Petersons' kitchen despite a court order that all witnesses preserve notes.

Campen explained during his testimony that the diagram, which depicted shoeprints rather than the footprints, was misleading and that prosecutor Jim Hardin Jr. had wanted another one made. Hudson told jurors that they could, but were not required to, draw an "adverse inference" against the prosecution. In other words, he explained, the jury could conclude that if the destroyed diagram were produced as the defense requested it could have benefited the defendant's case. Hardin re-read the entire instruction at the request of jurors.

Testimony resumes Aug. 6 at 9:30 a.m. The trial is being broadcast by Court TV.