UPDATE: Police arrest Buckeye mom in shooting death of 2-year-old son

Posted: Updated:
Alyssa Pettibone. (Source: Maricopa County Sheriff's Office/Buckeye PD) Alyssa Pettibone. (Source: Maricopa County Sheriff's Office/Buckeye PD)
A 2-year-old boy was shot and killed in Buckeye on Friday evening. (Source: 3TV/CBS 5) A 2-year-old boy was shot and killed in Buckeye on Friday evening. (Source: 3TV/CBS 5)
The toddler was dead when paramedics arrived but the 26-year-old was taken to the hospital. (Source: 3TV/CBS 5) The toddler was dead when paramedics arrived but the 26-year-old was taken to the hospital. (Source: 3TV/CBS 5)
Mug shot of Alyssa Pettibone. (Source: Maricopa County Sheriff's Office) Mug shot of Alyssa Pettibone. (Source: Maricopa County Sheriff's Office)
Driver license photo of Alyssa Pettibone. (Source: Buckeye PD) Driver license photo of Alyssa Pettibone. (Source: Buckeye PD)
BUCKEYE, AZ (3TV/CBS 5) -

Investigators say they have arrested the mother of a toddler who was shot and killed last week and say she could be facing a murder charge.

Police revealed on Sunday that a 2-year-old boy was shot to death and a woman, later identified 26-year-old Alyssa Pettibone, was stabbed in an incident that happened on Friday.

The two were found inside a home near Yuma and Watson roads just after 4 p.m.

[ORIGINAL STORY: Mystery surrounding Buckeye shooting incident]

According to court documents released Tuesday, Pettibone's mother called 911, advising that Alyssa shot her son Hudson Pettibone and then tried to kill herself. 

Alyssa's mother told police that she found Alyssa holding a gun to her head.

When officers arrived at the scene, they found a firearm next to Hudson's body in the bathroom. Police said the gun was used to kill the toddler. 

Officers also observed Alyssa lying on the floor and added she was bleeding from her neck.

While inspecting the handgun, officers discovered that a bullet was loaded backward, which caused the gun to jam.

[PDF: Form IV for Alyssa Pettibone]

According to court documents, Alyssa told one of the officers that she had just "shot her baby, and tried to kill herself."

Alyssa and the toddler were the only people at the house.

Hudson was dead when paramedics arrived but Alyssa was taken to the hospital. 

When officers interviewed Alyssa, she said she was sorry and added that "no one would understand." 

Police said Monday evening that Alyssa had been released from the hospital and was immediately arrested. She was booked on suspicion of second-degree murder.

Because she attempted suicide, Alyssa is in a "safe bed" in jail, which means she was not present for her initial appearance hearing. Rather, her lawyer was there on her behalf and asked the judge to consider a secured appearance bond rather than the $750,000 cash-only bond requested by the prosecutor.

"[A bond of] $750,000 cash is essentially de facto, 'She's being held without bond,' given the amount," Alyssa's lawyer said, pointing out that his client has "strong family support" and no criminal history.

[WATCH: Alyssa Pettibone's initial appearance hearing]

The judge went with prosecution's suggestion -- $750,000 cash -- and also mandated electronic monitoring and home arrest should Alyssa post and be released.

Arizona's Family reached out to the Department of Child Services to find out if the agency had contact with Pettibone in the past.

"DCS has received no prior reports involving Alyssa Pettibone," a spokesman told us via email.

Police say this continues to be an active investigation.

Alyssa's next court dates are a status conference on Dec. 22 and a preliminary hearing on Dec. 27.

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