The parents of a missing 21-year-old woman — who police say was kidnapped and murdered in April — have returned to Hawai'i from Japan four times since then to place flowers at the site of her disappearance and to help in the search for her remains.

Yesterday, Hideichi and Fumiko Watanabe of Japan made their first public appeal for information about the location of the remains of their daughter, Masumi.

"We are sure Masumi is on O'ahu," said the girl's father, appealing to anyone with information about the case to call the Honolulu Police Department Crime-Stoppers at 955-8300. Each time he and his wife have returned to Hawai'i, he said, they have placed flowers at the site on Pupukea Road where a witness said she saw Masumi Watanabe getting into a truck allegedly driven by Kirk Lankford, 22, of Kalihi.

Lankford has pleaded not guilty to charges that he kidnaped and murdered Watanabe on April 12. The case is built on circumstantial evidence because her body has never been recovered.

At the request of local law enforcement, the Watanabes yesterday would not discuss the criminal case or Lankford, although they did say they intend to attend Lankford's trial, which is scheduled to begin in February.

Overcome with emotion, Fumiko Watanabe, Masumi's mother, said yesterday through an interpreter, "It is important to find the body" and take Masumi home to Japan.

Hideichi Watanabe said on each visit to Hawai'i, he has rented a car and with the help of volunteers, has driven around, searching for his daughter's remains.

"We really want to have Masumi back as soon as possible. We really look for the information to take her body back to Japan," he said.

The public appearance was organized by local mortgage broker Bob Iinuma, who has befriended the distraught couple and operates a Web site about the case, www.findmasumi.org.

He said the couple overcame profound cultural differences to make the appeal yesterday.

Parents in such a situation in Japan "do not make any kind of public appearance," Iinuma said.

But "the public needs to see them, to feel their hurt and feel their loss," he said. Both parents "feel closer to Masumi when they are in Hawai'i," Iinuma said.

Hideichi Watanabe "would really like to be here for a month to do the searching himself" but is responsible for looking after his own parents in Japan, Iinuma said.

Asked to describe his daughter, he said yesterday, "She loved listening to music and (loved) the computer."

Masumi Watanabe spoke little English and was staying with a host family in Pupukea.

Police recovered Watanabe's DNA from the Hauoli Pest Control truck that Lankford allegedly drove, court records show. Eyeglasses also recovered from the truck allegedly matched Watanabe's prescription pair.

Last month, Honolulu Prosecutor Peter Carlisle lost a court bid to introduce eyewitness evidence from a woman who told police she was sexually assaulted in 2006 by a man driving the same truck that Lankford allegedly used to kidnap Watanabe.

Lankford was never arrested or charged in that 2006 case.

Carlisle said the 2006 complaining witness, an exotic dancer, physically resembled Watanabe and wanted to introduce evidence from the case in the murder trial because it would show the same "criminal signature."

Carlisle called the 2006 evidence "critical" to the murder trial.

Reach Jim Dooley at jdooley@honoluluadvertiser.com.