DURHAM, N.C. — In the midst of their case against novelist Michael Peterson, prosecutors were on the defensive Wednesday as they worked to counter defense claims that police were biased when they concluded Peterson's wife was murdered and not the victim of a horrific fall down a staircase.

To that end, Durham police officer Trent Hall testified that he became fond of Peterson after they met in 1999. Hall had e-mailed Peterson about the writer's columns in the Durham Herald-Sun, which  bluntly questioned whether the department was capable of solving crimes.

"We were arresting drug dealers. We were catching people breaking into houses," Hall testified. "I felt that he did not understand what we were doing as worker bees."

To give Peterson a closer look at a typical officer's experience, Hall invited him on a department-approved ride-along in his police cruiser, and the meeting formed the basis of a rare positive article about the police department.

When Hall picked Peterson up at his home that night, the officer was introduced to Peterson's children and wife, Kathleen.

"I can still remember her smile now," Hall said.

That was during the summer of 1999. Hall did not return to 1810 Cedar St. until hearing police radio transmissions about a death there on Dec. 9, 2001. Concerned that Michael Peterson might have been the victim, Hall went to the address with his police dog, a Belgian Malinois named Bosco.

Hall learned that he and his canine partner, since retired, were not needed at the scene just then, but the pair was dispatched to the house the next day to search for a weapon or other clues. Responding to a command Hall gave in Dutch, Bosco searched the entire grounds but failed to sniff out any evidence.

On cross-examination, Hall testified that a police supervisor, Sgt. Emanuel Paschall, was wrong when he testified Tuesday that to his knowledge the police department did not have any dogs capable of tracking scent.

"Surely, Sgt. Paschall knew that, right?" defense lawyer David Rudolf asked. Hall agreed that Paschall was aware of Bosco's training as a tracker.

Hall, the 20th prosecution witness during 11 days of testimony, testified about a photograph Paschall showed him that depicted a bloody indentation in one of the steps in the stairwell where Kathleen Peterson bled to death. At the time, Hall told Paschall that the mark looked like it was made from a tire iron or a fireplace poker, he said.

The prosecution maintains that a fireplace "blow poke" that should have been found in the Peterson home was missing — "mysteriously," the chief prosecutor said in his opening statement — after Kathleen Peterson's death. The defense claims the fireplace tool hadn't been used or seen by anyone for months or even years before the incident.

Because the small Polaroid lacked any ruler or scale that police crime scene photographs often include, Hall said he was unaware that the mark was actually only an inch in length, and not a few feet.

Another police officer testified Wednesday that Michael Peterson was angry when a half-dozen officers showed up at his home at about 6 p.m. on Dec. 12, 2001, three days after Kathleen Peterson's death. Peterson was preparing to leave for his wife's wake when police arrived unannounced with another search warrant.

Corp. Kim Gregory described Michael Peterson's mood the night of his wife's wake.

"Mr. Peterson asked, '[Do you] mind? I'm getting ready to see my dead wife in a coffin,''' Corp. Kim Gregory testified.

Police Lt. Connie Bullock explained in later testimony that police thought the Peterson house would be largely empty because wake visiting hours were 5 to 8 that night. "We thought it would be less intrusive, more sensitive to the family," Bullock said.

Michael Peterson never made it to the wake. He opted to stay during the search. Among things seized were his computer, computer records and documents assigning power of attorney rights to his two adult sons.

Another police officer, Steve Hester, told jurors that Michael Peterson appeared upset and was writing on a notepad in the pre-dawn hours of Dec. 9 as investigators waited for a court order to seize evidence. Peterson was in his study at the time.

"He would moan, cry, hold his hands to his head," Hester said.

A forensic meteorologist William Haggard began testifying Wednesday afternoon outside the presence of the jury about his analysis of weather conditions the night of Kathleen Peterson's death.

When Haggard returns to the stand on Friday, he may offer evidence to bolster a prosecution argument that it defies believability that Kathleen Peterson lay bleeding and dying from injuries sustained in a fall while her husband stayed in the backyard alone for as long as 45 minutes. Although it was December, well past midnight and chilly, Peterson was wearing a T-shirt and shorts at the time.

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