Idaho police on Friday dismissed a tipster who said he may have seen two missing children as the community where their mother, brother and a family friend were slain feared for the worst.

Kootenai County (search) authorities said a pawn shop owner's description of 9-year-old Dylan Groene and his 8-year-old sister Shasta was inaccurate and they would no longer pursue the lead.

The store owner said he saw two children with the driver of a light-colored, American-made, full-size van with Washington plates and a frame that said "Mount Shasta." The shopkeeper, in Bonners Ferry, 75 miles north of Coeur d'Alene (search), told police the driver, a tall white man, asked for directions to Libby, Mont.

Investigators checked highways and side roads between Bonners Ferry and Libby without success, according to the Boundary County Sheriff's Department (search).

Kootenai County Sheriff Rocky Watson said the description of the children was far enough off that they would no longer pursue the lead.

"We put an attempt to locate them, a description of the vehicle, particularly focusing on northern Idaho, western Montana and southern Canada area," Kootenai County sheriff's Capt. Ben Wolfinger said Friday.

Wolfinger told FOX News that evidence from the crime scene indicated the children may have been taken alive, but he would not elaborate beyond that. Watson said authorities didn't believe the children had been taken for sexual reasons.

The FBI has assigned an analyst to help prioritize tips investigators receive, Wolfinger said. Local law enforcement agencies or FBI offices are contacted to send someone to check out the higher priority tips, he said.

Some tips have come from psychics, or people who dreamed they saw the children, he said.

"The ones where someone says, `I had a dream' are not getting checked out nearly as quickly," he said.

Authorities have completed the crime scene investigation of a home where three people were beaten to death, but they had few clues about the disappearance of two children from the home. The search included an examination of 400 acres of brush and woods surrounding the family's home, and divers used their hands to feel the bottoms of nearby ponds and streams. .

"Ground crews are 100 percent certain the children are not here," Wolfinger said.

Sgt. Andy Boyle of the Kootenai County Dive and Rescue told FOX that divers felt confident there were no signs of the children in areas of water near the home.

"We just got a small section of a creek and then we’re done with all the water," Boyle said.

Also Friday, the children's father begged for the return of his kids.

"If they can see me or hear me, I want them to know I love them, I need them back with me," Steve Groene said in a televised interview. "Everybody's praying for them, and all I can tell them is please hang in there. This will be over soon. They're coming home."

Meanwhile, the community was trying to cope with the triple murder police believe preceded the children's abduction.

Coeur d'Alene School Superintendent Harry Amend told FOX News that teachers at the schools the children attended were trying to manage the shock and grief felt among classmates.

"At the beginning, there was hope those kids might have run into the woods. Right now, we don't think that's probably what happened. We're afraid that they're in the hands of the people that committed the crime," Amend said.

On Thursday, a concrete worker was cleared as a suspect in the slayings after authorities said he voluntarily took and passed a polygraph test during a seven-hour interview with investigators.

Robert Roy Lutner (search), 33, was one of the last visitors to the house where the victims — Brenda Kay Groene, 40; her 13-year-old son, Slade Vincent Groene; and her boyfriend, Mark McKenzie, 37 — were discovered.

Lutner told investigators he saw the three alive when he attended a "barbecue-type get-together" Sunday night at the family's home less than 24 hours before the bodies were found, Wolfinger said.

Watson said Friday that all the people who attended the event had been contacted but would not comment on whether they had been cleared in the investigation.

He said investigators would be questioning the guests to see if what they said about the house matched forensic evidence from the crime scene.

Lutner remained in custody on a probation violation warrant unrelated to the slayings and child disappearances, authorities said.

County Coroner Dr. Robert West said the victims were bludgeoned to death. He would not say when they died or what kind of weapon was used. The nature of the murder indicated more than one person was likely involved.

Forensic evidence from the crime scene was being sent to FBI headquarters in Quantico, Va., for analysis.

Wolfinger urged anyone who attended the Sunday gathering to contact the sheriff's office. Authorities have received pledges of more than $70,000 for a reward fund.

FOX News' Alicia Acuna and The Associated Press contributed to this report.