What to know about the puzzling disappearance of 9-year-old Melodee Buzzard

The puzzling disappearance of 9-year-old Melodee Buzzard has left many unanswered questions, with the local sheriff deeming the case "perplexing" and a law enforcement expert calling it "clearly suspicious."

Melodee, of Lompoc, California, has not been seen for more than two weeks, and her mom, Ashlee Buzzard, is not cooperating with investigators, according to the Santa Barbara County Sheriff's Office. The department has classified Melodee as an "at-risk missing person" and the FBI is assisting.

Here's what we know:

The last sighting

The sheriff's office said the investigation into Melodee’s disappearance was sparked when a school district administrator went to authorities on Oct. 14 to report her "extended absence."

Melodee was apparently homeschooled for at least the last few years, the sheriff's office said. This August, Melodee and her mom visited the Mission Valley Independent School to enroll her in the Lompoc Unified School District's "independent study program," according to the district.

"In our independent study program, if a student fails to pick up assignments, the student is referred back to their school of residence, which then contacts the family to complete enrollment," the district said in a statement. "If attendance does not begin, the school follows mandatory truancy procedures -- including phone calls, letters, emails, and home visits. When a student or family cannot be reached after these efforts, the school requests a welfare check from law enforcement."

Authorities later determined that the last verified sighting of Melodee was on Oct. 7, when she was caught on these surveillance images at a Santa Barbara-area rental car business.

"In the photo, Melodee is wearing a hooded sweatshirt with the hood pulled up and what appears to be a wig that is darker and straighter than her natural hair," the sheriff's office said. "Investigators believe the wig may have been used to alter her appearance."

Authorities said on Friday they narrowed down the window of Melodee's disappearance to between Oct. 7 and Oct. 10.

The mother and daughter took the rental car on Oct. 7 on a "three-day road trip" "from Lompoc to the Nebraska area, with the return trip including the state of Kansas," the sheriff's office said.

Ashlee Buzzard returned to her house on Oct. 10 with the rental car -- but Melodee wasn't with her, according to the sheriff's office.

"Detectives are now focused on determining where Melodee was during those three days and where she may be now," the sheriff's office said on Friday.

Investigators looking for Melodee would likely "check to see what history Melodee's mother has in this route" between California and Nebraska, ABC News contributor and former FBI agent Brad Garrett said on Thursday.

"Because, typically when people just roam off some place, there’s usually some purpose to it, a connection," said Garrett, who is not involved in the case. "Those locations that you have along the way, or the people that she knows potentially along the way, could really be helpful."

Investigators could track the road trip through the rental car and license plate readers, as well as through credit card use at hotels, gas stations or restaurants, Garrett said.

Through this data, Garrett said, investigators are looking to confirm, "can they actually put Melodee in this trip?"

An uncooperative mom

The sheriff's office said Ashlee Buzzard is not cooperating with the investigation and has not provided a "reasonable explanation of Melodee’s whereabouts."

"The last thing parents would do if they have a missing kid is be evasive," Garrett said. "So that’s a red flag."

He said the key to interviewing an uncooperative individual is getting them to provide timelines and facts that can be verified.

Investigators are likely doing their homework and conducting "a deep dive" on Ashlee Buzzard, he said, because "you want to know as much, if not more, as the person you’re talking to."

Garrett said interviewing people who know Ashlee Buzzard will also help answer questions like, "What were the circumstances in and around the house where Melodee and her mother lived? ... What was the relationship between Melodee and her mother? … How did she discipline the child?"

"All of those things are extremely important in assessing what you have," he said.

If Ashlee Buzzard continues to not cooperate, law enforcement may potentially threaten charges against her, Garrett said.

ABC News could not reach Ashlee Buzzard for comment.

An out-of-date photo

Until the surveillance images were released on Friday, the sheriff's office said the most recent photograph investigators had of Melodee is the one used on the FBI's missing person poster, which was taken two years ago.

"I think it's highly unusual that there aren't recent photographs," Garrett noted.

A search at the home

The sheriff's office said investigators have conducted searches at Buzzards' home and surrounding areas.

Garrett said a house search can provide a lot of valuable information.

"You would be looking in the house for anything that would lean toward foul play," like blood, he said, as well as evidence that gives date and time context, like completed schoolwork or receipts.

"Anything that would tangibly give you intel or information about potentially where she could actually be," he said.

'Come forward'

The public may be key to solving the case, Garrett said.

"If they know anything about this child, either currently or the past -- or maybe more importantly, about Melodee's mother -- they should come forward," Garrett said. “Unless the mother has lived in some sort of vacuum, she has worked some place, she has friends."

Garrett called the case "clearly suspicious."

"I'm concerned, based on what I'm hearing, that Melodee has already been in harm's way or is currently in harm's way," he said.

Santa Barbara Sheriff Bill Brown in a statement on Wednesday thanked the media for publicizing Melodee's disappearance and said he hopes that "will help us solve this perplexing case."

"We are hopeful that Melodee might be with someone -- perhaps an extended family member or friend -- who may not be aware of the circumstances of her disappearance," Brown said.

The sheriff's office urged anyone who has seen Melodee or has had contact with Ashlee Buzzard since Oct. 7 to call the department at 805-681-4150. Tips can be submitted anonymously at 805-681-4171 or www.sbsheriff.org/home/anonymous-tip.