Evidence implicating accused killer Kirk Lankford in a 2006 sexual assault case cannot be used in his murder case, a judge ruled yesterday, despite Prosecutor Peter Carlisle's argument that the evidence was "critical" to the murder case.

Lankford is accused of abducting and murdering Japanese national Masumi Watanabe April 12 on O'ahu's North Shore, but Watanabe's body has never been recovered and the case against Lankford depends almost entirely on circumstantial evidence.

Carlisle sought to include as evidence in the murder case testimony from an exotic dancer who told police in February 2006 that she was sexually assaulted by a man driving the same truck allegedly used by Lankford in the Watanabe case more than a year later.

Lankford was never arrested or charged in the 2006 incident and Circuit Judge Karl Sakamoto yesterday upheld defense attorney Donald Wilkerson's request to block any mention of the case from the murder trial.

Sakamoto said the circumstantial nature of the homicide case prevented inclusion of the 2006 evidence in the upcoming trial.

The earlier case involved allegations of sexual assault, but "there is no showing that this murder case involved sexual assault," the judge said.

"It is a difficult case with no body," Sakamoto said.

"The court doesn't know the cause of death to compare it with the previous case," he told Carlisle, and its value in the murder trial would be "outweighed by the prejudice to Mr. Lankford."

An obviously disappointed Carlisle declined comment on the judge's ruling after the afternoon court hearing.

During the hearing, Carlisle said the 2006 case would show the same criminal "signature" that was allegedly used against Watanabe.

The 2006 evidence "is absolutely critical to the successful prosecution of this (murder) case," Carlisle told Sakamoto.

The 2006 victim alleged that she was assaulted by a man driving the same Hauoli Termite and Pest Control truck that Lankford allegedly used in the Watanabe case, Carlisle said. The woman gave police the license plate number of the truck when she reported the Feb. 7, 2006, attack, he said.

Watanabe's DNA was recovered from the same truck after Watanabe disappeared, according to court files.

A witness reported seeing Watanabe getting into the vehicle on Pupukea Road the morning she disappeared. A pair of eyeglasses recovered from the truck matched Watanabe's prescription glasses.

The victims resembled each other, Carlisle said.

Both were "petite," weighing 100 pounds or less, both were short in stature and both were "very vulnerable," Carlisle argued.

The alleged victim in the 2006 case was an "exotic dancer with drug and alcohol issues," the prosecutor said.

Watanabe, 21, spoke little English; she was staying with a host family in the Pupukea area. Police described her as "shy and introverted."

Police questioned Lankford about both alleged victims, Carlisle said, but the defendant said he had never met either one.

But Wilkerson pointed out that Lankford was never arrested or charged in the 2006 case and argued that police weren't convinced an assault had occurred.

Lankford did not match the physical description the woman in that case gave of her assailant, said Wilkerson.

"The young woman reported an hour after the incident that the assailant had blond hair. Mr. Lankford obviously has red hair," Wilkerson said.

She said the attacker wore his hair in a crew cut and weighed approximately 160 pounds, but Lankford has never had a crew cut and weighs 205 pounds, the defense lawyer said.

Lankford, 22, of Kalihi, has pleaded not guilty in the murder case. Neighbors have described him as a churchgoing man, with a pregnant wife and a baby boy.

Reach Jim Dooley at jdooley@honoluluadvertiser.com.