The siblings, a 5-year-old boy and six-year-old girl, are safe after being handed over to law enforcement by two of the suspects.
The Tulare County Sheriff's Office says 29-year-old Makenzie Morelli, who is the children's biological mother, and 57-year-old David Steen were arrested.
Later Monday night, investigators announced that 28-year-old Kayla Williams was also arrested in Fresno.
Around midnight, deputies say they received a call for a burglary and kidnapping at a home in Earlimart.
The legal guardian of the siblings, which is their biological aunt, told police she was also assaulted when four people broke into her home.
"Those are very serious offenses, burglary, abduction, kidnapping. A whole Amber Alert went out because of this. People in this entire county and the surrounding counties in the entire state were woken up at 2 o'clock in the morning because of this. So, it is very serious," said Ashley Ritchie with the Tulare County Sheriff's Office.
Ritchie says it's likely the alleged kidnapper's received the emergency notifications on their phones.
"The suspect may have seen the Amber Alert, likely got it on her own phone and decided it was best to bring the children back," said Ritchie.
"So, without that Amber Alert coming out, I don't know how it would've turned out."
The California Highway Patrol is echoing the message from the sheriff's office about the importance of Amber Alerts.
"The Amber Alerts are of the utmost important, and we make sure that those aren't put out until all the steps are verified," said California Highway Patrol Officer Adrian Gonzalez.
Although the family says that children are safe and back home, the situation was still frightening for the victims involved.
"All we want is the best for the children and we're so grateful that it turned out the way that it did and they were brought back safely, but this is absolutely certainly gonna be a terrifying situation for those kids," said Ritchie.
Investigators say they are still working on tracking down one additional suspect.
Anyone with information is asked to call the Tulare County Sheriff's Office.
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