MADISON, Neb. (AP) _ A man was sentenced Friday to life in prison for the 1987 kidnapping a 9- year-old girl, whose mother forced a grand jury investigation and still doesn't know if her daughter is alive.

David Phelps showed no emotion when a judge imposed the sentence, saying: ''I want to state for the record that I am not guilty, but I do understand and respect what the court must do.''

Phelps, 27, was convicted March 20 of kidnapping Jill Cutshall with the intent of sexually assaulting her.

The girl was last seen Aug. 13, 1987, waiting on the porch steps of her baby sitter's home in Norfolk, a northeast Nebraska community of about 12,000. She has never been found.

''He's getting less than what he deserves, but I'll take this for now,'' said the girl's mother, Joyce Cutshall.

Mrs. Cutshall, dissatisfied with the police investigation into her daughter's disappearance, waged a petition drive at malls and stores to force a grand jury investigation.

Under Nebraska law, a judge is required to convene a grand jury if presented with petitions signed by at least 10 percent of the county's voters in the last gubernatorial election. Mrs. Cutshall collected 1,471 names, 447 more than required.

Madison County District Judge Richard Garden said that since Jill was not released alive or unharmed, state law required him to sentence Phelps to life.

Phelps, formerly of Norfolk, was arrested June 20 in Perry, Iowa.

Much of his three-week trial focused on a videotaped statement he gave to an Omaha television crew in January 1989. On the tape, which was played for the jury, Phelps said he held Jill at the Wood Duck Wildlife area in nearby Stanton County while another man molested her.

The other man, Kermit Baumgartner, 64, now of Lodi, Calif., took the stand and denied having anything to do with the disappearance. Phelps later recanted the videotaped statement. His lawyer claimed a private investigator pressured Phelps into the statement.

Phelps' lawyer, David Domina, said he plans to appeal to the Nebraska Supreme Court on grounds that the videotape should not have been admitted as evidence.

''I don't think there was any other evidence at all,'' Domina said.

Following the trial, Norfolk police said new information has turned up that might help them find the girl. Investigators have refused to disclose details.

Ms. Cutshall said she wants an assurance that Phelps would serve life without parole. Under state law, no one with a life sentence is eligible for parole unless a pardons board reduces the sentence to a specific number of years and a parole board grants parole.

''But I would be very surprised if that ever happened,'' said special prosecutor James Smith.

The girl's father, Roger Cutshall, who is divorced from her mother, said he was satisfied with the sentence but wants his daughter back.

''I'm still hoping,'' he said. ''I'd like to find out and I'm not going to give up the hope.''