Authorities weren't releasing many details, but one of the special circumstances filed by prosecutors against 42-year-old Marilyn Edge alleges the children were poisoned.
Edge, of Scottsdale, Ariz., is scheduled to be arraigned Tuesday. She was charged Monday with two counts of murder with special circumstances in the deaths of her daughter Faith and son Jaelen.
Edge lost custody of them on Wednesday in a Georgia case then texted her ex-husband, Mark Edge, two days later that she would bring the children back on Sunday, his attorney Marian Weeks said. The children were found Saturday in a Santa Ana hotel room.
Mark Edge was informed about the death of the children early Sunday by Atlanta police and was taken to a hospital for duress.
"He's emotionally, extremely distressed," Weeks said. "He is getting better. His whole focus right now is on the children."
Marilyn Edge could be eligible for the death penalty if convicted.
She was driving a car that crashed Saturday into an electrical box outside a shopping complex in Costa Mesa. She refused to get out of the car and tried to choke herself with an electrical cord as rescuers attempted to free her, Santa Ana police Cpl. Anthony Bertagna said.
Police found propane in the car but wouldn't say whether there was a suicide note.
Authorities said Edge told investigators they could find her children's bodies at the hotel.
The Edges were married for less than 10 years and divorced in December 2007, Weeks said. Marilyn Edge claimed her former husband, who routinely traveled to Afghanistan where he worked as a contractor, failed to make child support payments, according to court records.
She also claimed the children of a friend of her ex-husband were sexually abusing her kids, but the allegations were never proven, Weeks said.
Marilyn Edge was given full custody of her children in October 2009, a ruling that was later set aside after Mark Edge contended he wasn't aware of a court hearing because he was overseas and documents were sent to a wrong address. However, the Georgia Supreme Court later found there wasn't enough evidence to set aside the ruling.
Weeks said the case began to turn in the ex-husband's favor in September, when a judge reduced child support payments and ordered joint custody. At the time, Edge hadn't seen his kids in more than 1 1/2 years because his ex-wife refused to let him visit, the lawyer said.
Mark Edge was stymied again by his ex-wife, who moved to Arizona shortly after the judge's order, saying she was getting a job transfer. He only saw his children three or four times via video phone calls, Weeks added.
"All he wanted was to spend time with his children," Weeks said. "But Marilyn could not let that happen."
At a hearing last Wednesday in a Georgia courtroom, a judge found that Marilyn Edge was alienating her children from her ex-husband and said he should be given full custody, Weeks said. It's customary for the custody transfer to happen the same day as the judge's order, Weeks said, but Marilyn Edge said the children were staying with her parents in Arizona.
The judge gave her until noon Sunday to turn over the children. On Friday, Mark Edge received a text from his ex-wife saying, "'I will see you on Sunday and I have their school records,'" Weeks said.
Lawyer Mary Ann Korre said she had only represented Marilyn Edge at the most recent child custody hearing and had only known her client a few weeks.
She wasn't aware of any reason why her client wouldn't want her ex-husband to have contact with the children. Marilyn Edge was calm at the last hearing and there was nothing to indicate she might harm the kids, Korre said.
"I received the news yesterday and I was just very shocked," she said. "It's just a very tragic situation."
AP Writer Kate Brumback in Atlanta contributed to this report.