A witness in the Thomas E. Murray murder trial testified Friday about one of the case’s more puzzling pieces of evidence: a wavy blood stain found on the lip of a bathroom sink in the victim’s home.

Mike Van Stratton, lab director for the Kansas Bureau of Investigation, said that when he examined the stain, his first opinion was that it came from a shoe.

But the pattern doesn’t match any of the shoes seized from defendant Murray, the Kansas State University professor accused of killing Carmin D. Ross, his ex-wife, in November 2003. Just as importantly, it doesn’t match a different, unexplained shoeprint found not far from the bathroom on the carpet of Ross’ home.

“Neither of those two shoe prints match anything, to your knowledge, belonging to Mr. Murray?” defense attorney Pedro Irigonegaray asked.

“That’s correct,” Van Stratton replied.

Defense attorneys have seized on Van Stratton’s finding as they argue to jurors that there were at least two unidentified people in Ross’ home northwest of Lawrence at the time of the killing.

Van Stratton, however, testified that it was only his preliminary opinion that the print on the bathroom sink came from a shoe. The print, he said, also could have come from a piece of fabric with a wavy pattern.

Assistant Dist. Atty. Angela Wilson asked Van Stratton whether he’d ever been an expert in shoeprints. He said he hadn’t.

6News video: Kansas State students testify against former professor (03-04-05) Photo Gallery: Murray Trial Day Eleven See complete trial coverage

Van Stratton also testified that, based on his analysis of blood stains found throughout Ross’ living room, he believed there was a struggle that moved across the living room. Blood spatters indicate Ross was low to the ground and was “struck multiple times while in different positions,” Van Stratton said.

Other witnesses Friday included three K-State students who took Murray’s English class the semester in which Ross was killed. One of the students, Linda Carrigan, testified that the day before Ross’ death, Murray graded her test in the classroom as she stood and watched.

Thomas E. Murray, right, talks with defense team Pedro Irigonegaray, foreground left, and Robert Eye, center, during the 11th day of his murder trial.

Murray told detectives that on the morning of Ross’ death, he was grading papers all morning in the kitchen of his Manhattan home. He later changed his story to say he’d taken a drive toward Topeka to “clear his head” and to shop for pillow covers in Paxico.

He told detectives he got on Interstate 70 but turned around and came home.