DEDHAM, Mass. (Court TV) — "Bloody grab marks" were on the sleeves of the windbreaker Boston allergist Dirk Greineder wore the morning his wife was bludgeoned and stabbed to death, a blood spatter expert testified Friday.

The chilling implication presented jurors with a picture of a dying Mabel Greineder clutching onto her husband's windbreaker as he, according to prosecutors, bludgeoned and stabbed her.

The sleeve of Greineder's windbreaker has "bloody grab marks," according to prosecution expert Rod Englert

But it wasn't the prosecution's only visual advantage as testimony continued Friday in the first-degree murder trial of Greineder, who is accused of killing his wife to pursue a secret life of porn and prostitutes.

The jury got to see the blood stains on the actual windbreaker modelled by a life-sized mannequin dressed from head to toe in the clothing Dirk Greineder wore on Oct. 31, 1999, the day his wife was slain in a wooded park near the couple's Massachusetts home.

As he testified, prosecution witness Rod Englert alluded to the dummy, which was clad in the yellow windbreaker, black and red shirt, and black pants, and placed under a spotlight for a good portion of the day's proceedings.

The clothes worn by Greineder were covered in black marks, once red with Mabel Greineder's blood.

While the defense claims that the Harvard-educated physician got his wife's blood on him while he tended to her after discovering her body near Morse's Pond, the prosecution set out to prove that the blood was propelled on to Greineder's clothing while she was being beaten with a hammer and stabbed with a knife.

Englert demonstrates to the jury using the mannequin wearing Dirk Greineder's blood-stained clothing

Englert said more than 10 of the blood stains — now black and very prominent on the bright-yellow windbreaker — were impact stains, not transfer stains that got on the jacket after the murder occurred. His analysis also revealed impact stains on other items Greineder wore, including the shirt and pants.

The stains on the windbreaker were consistent with Greineder moving his dead wife's body from behind, he said, during direct examination by prosecutor Richard Grundy.

Another key piece of testimony the defense may find difficult to overcome is Englert's analysis of Greineder's glasses, on which were found specks of blood.

These specks formed a pattern Englert said was consistent with a blood-covered glove found near the crime scene and believed to be used by the killer. The material of the glove's texture was covered with what he termed "mini-dots," a pattern which he said could account for the pattern of blood found on the glasses' lenses.

The same mini-dot pattern was also found on the murder weapons, a hammer and a knife, both of which were found with the glove.

Englert's analysis of the glasses was based on a photograph taken by police before Greineder left the scene. Claiming he needed the glasses to drive home, Greineder wouldn't turn over the glasses to the detectives until later — and they were wiped clean.

Robert Stites, the crime scene re-constructionist who processed the photo, was called to the stand in the middle of Englert's testimony. The photo was admitted despite the objection raised by the defense over the digitally-enhanced image.

Rod Englert

The defense was successful in keeping some evidence of stains on the windbreaker out of the trial. Stains on the back of the windbreaker — which the prosecution claims could show that the blood spatters landed there while the killer swung the hammer between blows to the victim — were ruled inadmissible.

The defense successfully argued that while the stains were tested for protein that is found in blood, there were no tests performed to determine that the protein was in fact derived from blood and not another substance.

During his cross-examination, defense lawyer Martin Murphy attempted to rip apart the scientist's credibility, charging that he consulted with a psychic and also used hypnosis in previous cases. Englert, however, denied using psychics and said that he no longer uses hypnosis.

Englert's testimony marks the second expert in as many days to indicate Greineder was present when his wife was murdered. The 60-year-old doctor has maintained that he and his wife were playing with their dog near the pond, when Mabel Greineder separated from her husband to return home because of back pain.

On Thursday, Lt. Kenneth Martin testified that Greineder's sneakers and windbreaker show impact spatters that would put Greineder near his wife's body as she was being murdered.

Martin again took the stand Friday morning for cross-examination, and maintained his composure as Murphy attacked his credentials.

Englert, who is expected to be the last witness for the prosecution, will continue his testimony when court resumes Monday at 8:30 a.m.

The trial is being broadcast on Court TV.