CALIFORNIA CITY, Calif. — In any missing person's case, authorities often highlight the importance of the first 48 to 72 hours of an investigation.
Within that time frame, investigators have the best chance to generate leads, preserve evidence and obtain accurate information.
According to former Bakersfield Police Department Lieutenant Gary Carruesco, the chances of a successful outcome begin to fade past that period and for missing children, that timeline moves even faster.
Three-year-old Orson West and 4-year-old Orrin West have been missing since Dec. 21, according to what their adoptive parents told the California City Police Department.
"What stands out immediately is the fact they haven't found these boys yet," Carruesco said. "You know it's been several days."
Carruesco has worked a lot of missing person cases within his 20 years serving BPD. He says the investigation starts with a few mandatory steps.
"So obviously you want to know the immediate set of circumstances that led to them being missing or disappearing. You want to focus on those that know them the best."
Trezell and Jacqueline West are the boys' adoptive parents. They told 23ABC News in their first and only media interview Wednesday, that the boys were playing with chalk in the backyard of their Cal City home when they suddenly went missing at about 4:30 or 5 p.m.
Trezell West said he was gathering wood to start a fire, while Jacqueline was wrapping Christmas presents, when the incident occurred.
Jacqueline West old 23ABC that she thinks the boys were kidnapped.
"They do not just roam around these patches, they definitely would have been picked up or something," West said.
The FBI has been assisting CCPD and the Kern County Sheriff's Office with the investigation.
While the agencies sort through several leads in the case, Carruesco says no one is completely ruled out as a suspect in these cases, until the boys are found -- not even the adoptive parents.
The couple has been seen leaving with law enforcement several times by 23ABC crews and residents who live nearby. Neither time were they handcuffed and CCPD has still not publicly named a suspect in the case.
As several residents in the community have accused the parents of foul play, Carruesco says people shouldn't jump to conclusions and consider all possibilities like whether there are any sex offenders or suspicious people in the area.
According to the Megan's Law website, a California Department of Justice's operated domain, there are 14 convicted sex offenders within two miles of the missing boys' home. Two offenders live less than a mile away from the home.
While it is unclear whether authorities have contacted any of these offenders, Carruesco was using the scenario as an example of how many circumstances law enforcement must consider, when deal with a missing person's case.
"There is a lot of factors that are working against the investigators in the community so that's again the reason so many resources are brought in immediately," Carruesco said.
One major factor -- hundreds of miles of sprawling desert surrounding the small town of California City.
Residents have launched their own search efforts several times, so far -- no sign of Orrin and Orson.