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Forensic expert Douglas Deedrick testified Thursday about the various tests he conducted during the investigation into the mysterious circumstances of D.C. attorney Robert Wone‘s death in 2006.

Three of Wone’s friends,housemates Joe Price, Dylan Ward, and Victor Zaborsky, are accused of conspiring to cover up Wone’s killing. The defendants maintain that Wone was killed by an unknown intruder while he slept in their guestroom, using a knife that came from a butcher’s block located in their kitchen.

Hoping to establish how many fibers would be left on a knife plunging in and out of a shirt similar to the one Wone wore the night of his demise, Deedrick said he employed a piece of pork.  “I purchased about an eight pound pork loin as a substance to stab into,” the former FBI special agent testified. Deedrick fitted the meat with a black Tultex t-shirt and began thrusting.

Rachel Lieber, a lawyer for the prosecution, asked if the skin was on or off. Though Deedrick couldn’t remember, he noted that the piece of meat “wasn’t a fillet.”

Deedrick said the knife the housemates identified as the one that murdered Wone had shorter material fibers on it than knife in the test. That conclusion may bolster a contention of the prosecution, that Wone was murdered by a totally different knife that the housemates may have ferreted away.

Another test Deedrick did involved a towel soaked in horse blood. Deedrick used the equine fluid to figure out what sort of pattern a bloody towel would make on a knife if the two came in contact. Similar patterns were found on the knife investigators found next to Wone’s body. The prosecution believes the three alleged conspirators put some of their victim’s blood on a knife that wasn’t the murder weapon, using a bath towel.

On cross-examination, defense attorney David Schertler held up an enlarged photo of the blood specked knife found next to Wone. The picture showed what may have been hairs and at least one chunk of what appeared to be body fat on the blade. When Deedrick examined the knife in December 2006, he saw neither. That could mean evidence fell off the blade before it was given to him.

“If important stuff like hairs fall off, it compromises the information you’re able to give us, correct?” asked Schertler. Deedrick conceded to that point.