Youngest children ever to be tried as adults for first-degree murder to be released

A brother and a sister who were the youngest people to ever be tried as adults for first-degree murder in the United States are set to be released in the next nine days, according to authorities.

Curtis and Catherine Jones were 12 and 13 years old, respectively, when they were convicted in the killing of their father's girlfriend. Curtis, now 29, and Catherine, now 30, pleaded guilty to second-degree murder in the 1999 killing of Nicole Speights, according to Florida Today.

The siblings from Cocoa Beach, Fla. had accused a male relative of sexually abusing them, according to ABC affiliate WFTV. The two sought help from their father and his girlfriend, but their pleas were ignored. The two then plotted to kill their father, his girlfriend, and their alleged abuser.

After the siblings had shot Speights, they became scared and didn't go ahead with their plan to kill the other two people, according to Florida Today.

Prosecutors told ABC News on Thursday that the children had killed Speights out of jealousy, and that the alleged abuse came out in later press accounts that were not dealt with in court.

The siblings were given 18-year prison sentences and will be on parole for the rest of their lives, according to ABC News. During their imprisonment, Curtis was ordained as a minister while Catherine married a pen pal, according to Florida Today.

"Of course there are fears, mainly because there's so much I must learn to function like a normal person," Catherine wrote in a letter to Florida Today in 2014. "How to drive, fill out job applications, text, dress for a job interview, build my credit."

Curtis is set to be released from Florida's South Bay Correctional Facility on July 28. Catherine is scheduled to be released from Lowell Correctional Institution near Ocala, Fla. on Aug. 1.