DURHAM, N.C. — Someone with blood on their bare feet walked from the hallway where Kathleen Peterson was found dead to a utility sink in the laundry room.

The faint footprints then lead into the kitchen to the refrigerator and sink, and finally to a cabinet where wine glasses were kept, according to testimony Thursday at novelist Michael Peterson's murder trial.

Police evidence technician Eric Campen told jurors that the trail was only visible when investigators sprayed the floor with luminol, a chemical that emits a blue-green glow when it reacts with traces of blood even after the blood is no longer visible because it has been wiped away.

Sound suspicious? Prosecutors hope so.

Durham District Attorney Jim Hardin Jr. hasn't connected the dots for the jury yet, but he is clearly putting on evidence to show that the 59-year-old defendant may have done a great many things before calling 911 on Dec. 9, 2001. Peterson, a novelist with four books to his credit, claimed he found his wife injured but breathing at the bottom of a narrow, dimly lit stairwell.

Kathleen Peterson, 48, was dead when the first emergency workers arrived. Police saw all the blood, became suspicious, and so began one of the most tantalizing mysteries in decades to play out in this county of 250,000 people.

An example of luminol-revealed footprints from an unrelated case

Campen, the prosecution's 25th witness during four weeks of testimony so far, has been a much more solid witness than a fellow evidence technician who was on the stand for five previous days of the proceedings. When Campen offered explanations for things he did and did not do, without even being asked, defense lawyer David Rudolf merely shook his head but didn't interrupt to object.

One bone of contention during the previous evidence technician's many hours on the witness stand was that police did not attempt to photograph the luminol reaction he and Campen said they observed on the kitchen floor.

Dan George, the first evidence technician, did not have an answer for why the procedure was not photographed. Campen, in contrast, volunteered that, while it was dark enough to see the reaction with the naked eye, outside lights that flooded the kitchen made such photography too difficult.

Without prompting, Campen volunteered that, although the crime scene technicians carry black plastic that could have been used to block the outside light, there wasn't enough plastic to cover all the windows.

No evidence yet suggests that the hidden footprints were made by Michael Peterson. But neither has there been testimony that anyone other than him was walking around the house in bare feet. If the defense ends up conceding the footprints were made by the defendant, they may need to offer an explanation of either who cleaned them up or why they were only visible when luminol was applied.

Like previous police witnesses, Campen testified that the blood he saw made him suspicious that Kathleen Peterson's death may not have been from a fall. More specifically, he was concerned that apparent blood spatter was not limited to the stairwell and some stains were significantly higher on walls than where the body was discovered.

Prosecutors contend this happened when a deadly instrument — either a fireplace poker or something similar — sprayed droplets as it was forcefully swung to and fro.

"It seemed unusual. It wasn't the amount of blood," said Campen. "I've been to bloodier scenes. It was just so high" on the wall.

Rudolf has yet to cross-examine Campen, but he'll likely ask the state's witness whether he's been watching the trial on television or was extensively prepped on the issues by the prosecution or other witnesses.

Rudolf seemed prepared to rebut all incriminating questions, including the issue of the amount of blood. The defense previously entered into evidence a photo of an unrelated death from a fall where the appeared to be more blood than was present when Kathleen Peterson died.

No one in the Peterson case disputes that there was a tremendous amount of blood, but the defense has hammered the point that people who bleed to death even from accidental injuries spill a lot of blood as they lie dying.

Campen, who is expected to be on the witness stand all of Friday and perhaps longer, also testified about collecting a "used" condom and wrapper from the master bedroom. Judge Orlando Hudson Jr. allowed the testimony over defense objections.

The condom may prove relevant when the prosecution tries to introduce evidence about documents and files found on Michael Peterson's computer.

No one used the phrase "gay pornography" in court, but that's how the local media has described some of the evidence that has yet to be introduced in this trial.

Prosecutors have maintained that Kathleen Peterson was killed for $1.4 million in insurance money but, to counter the defense's portrayal of the Peterson's marriage as a "storybook" one, they may try to introduce evidence that Michael Peterson engaged in or fantasized about an alternative lifestyle.

Hudson said he would rule on the issue of the "reading materials" and computer files if the prosecution decides to go down that road.

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