(CNN) -- Elizabeth Johnson -- whose 8-month-old baby, Gabriel, disappeared in 2009 after she allegedly took him to Texas -- was found guilty Thursday of unlawful imprisonment and custodial interference.
Johnson also was originally charged with kidnapping, but the jury couldn't reach a verdict on that charge.
Instead, the jury found her guilty with aggravating circumstances on the lesser charge of imprisonment and two custodial interference charges. Her next appearance in court will be November 1 when the judge will set a sentencing date. She has already served nearly three years in jail, having been taken into custody shortly after Gabriel disappeared.
He was 8 months old when he was last spotted alive at a Texas motel in late 2009. What happened to him is unclear. Johnson originally told the boy's father that she had killed Gabriel, but after she was arrested, she told police that she gave the baby to an anonymous couple in San Antonio, CNN affiliate KPHO-TV reported.
Police in San Antonio searched a landfill and found nothing. There also have been searches in Arizona and Florida, according to HLN, the sister network to CNN.
The San Antonio police website lists Gabriel as a missing person.
The mystery began December 17, 2009, after a judge awarded Johnson and Logan McQueary, the boy's father, joint custody of Gabriel. But Johnson allegedly defied the ruling and set out for Texas with her son.
McQueary didn't hear from Johnson until several days later, when she reportedly sent him a text message saying she'd killed Gabriel and put his body in a Dumpster.
"I killed him," Johnson said in a text to McQueary on December 27, 2009. "U will never see Gabriel again, I made sure of that. And you can spend the rest of ur pathetic life wondering about him."
The scathing series of texts continued.
"U will never find me im already bording a plane. Out of the country," Johnson said. "When im safe ill email u the exact location of dead gabriels little blue body. If the garbage don't come first."
McQueary also recorded a phone call from Johnson in which she made similar claims.
Johnson: "You made me do this."
McQueary: "You did not hurt Gabriel."
Johnson: "Yes, I did. I suffocated him. .... I suffocated him and he turned blue. And I put him in his diaper bag and I put him in the trash can."
Johnson was arrested on December 30, 2009, in Miami Beach, Florida.
She told police she gave Gabriel to a unknown couple under the direction of a woman named Tammi Smith.
Johnson and Smith had met in June 2009, when both women were waiting for the same flight in the Indianapolis airport.
Smith suggested to the young mother that she and her husband adopt Gabriel. Johnson said she called Smith that December to ask if the couple was still interested.
In May, Smith was found guilty of forgery and conspiracy to interfere with Gabriel's custody. She was sentenced to probation and 30 days in jail.
Smith's conviction does not relate to the boy's disappearance, but her efforts to conspire with Johnson to deny McQueary his rights to see his son.
Smith told the court that she helped Johnson and helped care for Gabriel for nine days.
Smith eventually apologized for any "pain and suffering" that helping Johnson may have caused, even as she firmly insisted that her intentions were good.