Dirk Greineder had no blood on his hands, even though he had tried to lift his wife's bloody body off the ground where she lay after a brutal attack. The prosecutor trying the Boston doctor for his wife's murder attempted to bring this point home Wednesday during Greineder's final day on the stand.

Pressed to explain why a police photograph taken after his wife's murder showed his sleeves marked with blood down to the cuff, but his hands stain-free, the Boston allergist could muster only a curt "I don't know."

"Those were the hands you used in those three attempts to pick up your wife?" asked prosecutor Richard Grundy.

"Yes," replied Greineder.

The prosecution contends that Greineder, 60, murdered his wife, Mabel Greineder, in a park near their Wellesley, Mass., home on October 31, 1999, because she found out about his secret life of Internet porn and prostitutes. Grundy suggested in court that the doctor had clean hands because he covered them with a pair of gloves during the murder and then discarded the gloves along with the murder weapons, a sledgehammer and knife, in a nearby storm drain.

The defense says Greineder walked ahead of his wife in their usual walking circuit and returned to find her slain by an unknown killer.

During Greineder's third day on the stand, Grundy continued grilling him on inconsistencies in statements he made during his recent testimony and after the murder, and also attacked new information that Greineder provided in direct examination.

At one point, Grundy asked Greineder to explain how he crouched down to pick up his wife, even offering himself as a mannequin. "Like this?" he asked Greineder after showing him several postures.

Greineder was reluctant to pose the prosecutor, but said, "My usual habit was to pick up something heavy with one knee down and one knee up. That's just what I learned to do with my legs."

Greineder answered Grundy more confidently Wednesday than he had Tuesday, and at one point even looked toward the jurors, shook his head and rolled his eyes with a smile. But his testimony was not as emotional as the tearful accounts he gave Monday and Tuesday.

Grundy pressed Greineder on his secret sex life, attempting to cast it as an obsession rather than a secondary pursuit, as Greineder testified Tuesday. Forced to describe a "New York experience," Greineder told jurors he had been in the city for a conference when he decided to hire a prostitute. After a fruitless Internet search, Greineder told the courtroom, he decided to use the yellow pages to find a woman. At 2:46 a.m., Greineder called one escort service and then went to the hotel lobby to withdraw $300 in cash. The prostitute came to his hotel and, after she left, Greineder ordered a pornographic movie at 3:46 a.m. He then went on the Internet again at 5:50 a.m.

The prosecutor seized on this night-owl behavior to ask whether Greineder frequently stayed up late to engage in his secret sexual pursuits. "Isn't it true that your side activities had become a large part of your life, that they kept you up all hours of the night?" Grundy asked. Greineder denied that assertion.

Grundy also paid much attention to Greineder's allegedly deviant sexual activities. "Sir, assuming that sexual intercourse, [is] regular vaginal sex, you asked to perform acts other than that?" he asked.

"Yes," said Greineder.

Grundy then attempted to delve into Greineder's participation in "bondage" activity, but with limited success. The prosecutor asked Greineder to explain what he did with a small loop of white rope with two thick knots at the end, but the defendant's answer was mundane.

"This is a contraption based on something from a travel magazine," Greineder replied, noting how the knots would hang over the top of a closed door and allow one to hang a travel bag for suits on the loop on the other side.

Grundy received a different reaction when he asked Greineder about the kinds of "toys" he enjoyed using.

"At one time" admitted the defendant, "I had a vibrator."

Because Greineder had downplayed the importance of sex in his life during his direct examination, Grundy asked him whether he were underestimating the role of his secret obsessions.

"It didn't interfere with the love you had for your wife?" asked Grundy skeptically.

"I love my wife, that's all I can say," returned Greineder.

Grundy also tried to show that Greineder had a lot to lose if his exploits were made public and might take extraordinary steps to prevent that disclosure.

"Would it have been devastating to your career, your family, your children if any of this was known?"

"It would have been upsetting," Greineder replied.

The prosecutor wrapped up his cross-examination by holding up the items found near the murder scene one by one. "You don't know anything about these gloves, did you?" he asked. "You didn't know anything about this knife?"

Each time, Greineder said "No."

On re-direct and re-cross-examination, Greineder offered an explanation for the phone call he made to the prostitute named Doolio the day after his wife was murdered. He said he left a message for her on October 30, 1999, and called her again on November 1, 1999, the day after the murder, because he'd given his phone to one of his children and was afraid she'd call.

"I had no choice but to call and protect my kids from that call," he told the jury. "I said I did not want to see her again."

"Did you tell her 'I've done what I've been planning to do, the coast is clear'?" prompted defense attorney Martin Murphy sarcastically.

"No," replied Greineder

Murphy fared poorly with his third witness, Joseph McGloin, a sales manager for Gloves, Inc.

McGloin testified that he had sold about 60,000 pairs of gloves like the ones found in the storm drain to a store in Greineder's area in the past decade. Murphy hoped to show that the gloves found in the storm drain could have belonged to anyone. But on cross-examination, when Grundy asked McGloin to compare a sample of his gloves with the gloves found in the storm drain, the salesman stopped short and Murphy's strategy backfired.

"Is this exhibit number two one of your gloves?" asked Grundy. McGloin said no, then added, "Mine's a better glove." Murphy spoke with disappointment as he asked his witness again whether the gloves were the same. "Are you sure?" he said, appearing distraught. McGloin once more said they weren't, to which Murphy replied "Well, if I had known that I wouldn't have drawn you all the way out here," and returned to his table.

Murphy also called two witnesses aimed at dispelling the idea, put forth by the prosecution, that Greineder had financial reasons to kill his wife.

Joseph Stone — Greineder's insurance agent, whom the doctor had treated for asthma and had known for more than 20 years — testified that the insurance policy the doctor had applied for, but never enacted, wouldn't have benefited him in the event of Mabel Greineder's death. Greineder smiled widely at Stone, a break in the defendant's generally sullen countenance.

Jeffrey Schlossberg, an estate planner for the Greineders, testified that he helped the family minimize the estate tax that would be levied on the children's eventual inheritance.

Murphy may not get a chance, however, to rebuff one of the prosecution's most damning pieces of physical evidence — the presence of Greineder's DNA on the items used to kill his wife. The defense's theory is that DNA could have been transferred from Greineder to his wife, and then to the killer during the attack.

In an impromptu voir dire hearing that began at 7:30 a.m., continued during lunch, and then again after the jury was dismissed, Murphy battled to convince Judge Paul Chernoff that DNA expert Marc Taylor should be allowed to testify. Taylor performed a series of experiments Murphy says show DNA can be transferred from one person's cheek to another, and then onto a glove.

But Chernoff expressed doubt about the strength of Taylor's experimental methods and did not rule on the witness.

The trial, which is being broadcast live by Court TV, continues tomorrow at 8:30 a.m. ET.