If little Dylan and Shasta Groene (search) are still alive — and the sheriff desperately wants to believe so — they may have a ghastly story to tell.

Dylan, 9, and Shasta, 8, were abducted a week and a half ago, probably after they witnessed their mother, her boyfriend and an older brother being bound and then bludgeoned to death inside their rural home, authorities say.

After searching across the Northwest and fielding more than 1,150 tips, the FBI and local investigators say they have no suspects, no strong leads as to the children's whereabouts, and no idea why the victims were killed and the youngsters taken.

But they are not giving up hope.

"I have a need to believe those children are still alive," Sheriff Rocky Watson (search) said.

The children's mother, Brenda Groene, 40, older brother Slade, 13, and their mother's boyfriend, Mark McKenzie, 37, were killed inside the white, cinderblock house a few miles east of town. Brenda Groene and other members of the family had been mixed up in drugs and petty crime over the years, but investigators have not publicly connected any of that to the slayings.

Watson has speculated there was more than one killer because all the victims were bound. Officers also suspect the killer was known to the victims, because there was no sign of forced entry.

Public suspicion has centered on Steven Groene, 48, ex-husband of Brenda and father of the three children. But deputies insist he is not a suspect, even though he has no alibi for the night of the slayings, failed a lie detector test when asked if he knew the whereabouts of the children, and issued a puzzling public plea to the abductors.

"Please, please release my children safely," Groene said last week. "They had nothing to do with any of this."

Officers could not say what "any of this" referred to.

Because their home was close to Interstate 90, just west of a pass in the Rocky Mountains, investigators have said it is possible that a motorist committed the crimes at random and then jumped onto the highway heading toward Montana or Seattle.

The Groene family lived on the edge of this Idaho Panhandle community, both physically and financially. Coeur d'Alene (search) is a booming resort and retirement town, thanks to its postcard lake and abundant golf courses. Like many resort areas, it is also home to people like the Groenes, struggling to get by on low-paying jobs.

Steven and Brenda Groene were married in 1986 and had five children before they divorced in 2001. Steven Groene said in a TV interview that they had squabbled over issues such as visitation rights as recently as a few days before the slayings, but otherwise got along.

Steven lived with his former mother-in-law, and Brenda lived in the home owned by McKenzie, who is her cousin. Slade, Dylan and Shasta lived with her. Of the two older children, Jesse, 18, is in jail on burglary charges. Vance, 20, had a juvenile record. Both older brothers have had problems with drugs.

Steven Groene, 48, is a blues musician who plays in a band called Blue Tattoo. He has acknowledged heavy narcotics use in the past, and was arrested once for battery. At the time of her death, Brenda was on probation for possession of drug paraphernalia. She had been ordered into drug and alcohol counseling.

The county coroner said Brenda Groene and Mark McKenzie had illegal drugs in their systems.

Early on, officers focused on a party that the couple threw at the home on May 15, the last time they were seen alive. The bodies were discovered in the house the next afternoon. A friend who was identified as being at the party was briefly considered a "person of interest" before authorities cleared him.

As for Steven Groene, sheriff's Capt. Ben Wolfinger said investigators attribute his flunking of an FBI polygraph to emotional distress.

"I can assure you that neither any family member nor I could ever possibly be so barbaric and evil," Groene wrote in an e-mail to KREM-TV of Spokane this week, adding he was confident law enforcement officers would catch "the animal or animals."

Investigators are chasing down leads and circulating photos of the children, along with a home video of Shasta at a recent school science fair. At Davis Donuts in Coeur d'Alene, a sign reads: "Pray for the safe return of missing children Shasta and Dylan Groene. God Bless Them."

Crowds of campers are expected in the area over the Memorial Day weekend, and sheriff's deputies are asking them to report any sign of the youngsters.

"We ask if anybody camping in those grounds sees anything suspicious, please don't touch it. Contact law enforcement," Wolfinger said.