In a case that made international headlines, Jeen "Gina" Han was sentenced to 26 years to life in prison in May 1998.
A report released Tuesday says Gina Han was recommended for parole on Oct. 31.
Under state law, the decision includes a 120-day review period so Gov. Jerry Brown can decide whether to approve or reject the recommendation.
The Orange County District Attorney's Office in a letter asked Brown to reject the recommendation, saying Gina Han is still a risk to society because she never addressed her alleged mental disorder.
Deputy District Attorney Nikki Chambers said Gina Han's pen pals from abroad and across the country have offered her money, jobs and lodging, including a man from Britain who gave her money after corresponding for a year, the prosecutor said.
"The fact remains that she is still flexing the manipulation muscles that she used when she recruited two young men to murder her sister, and they appear to be as keen as they were in 1996," Chambers wrote.
Han and two others were found guilty of conspiracy to commit murder, burglary and false imprisonment. Prosecutors said the three plotted a failed plan to murder Sunny Han, who was bound and gagged along with her roommate until police came to their rescue.
The Korean-born twins were co-valedictorians at their San Diego County high school, were once close but had a history of fighting, authorities have said. Their relationship deteriorated after Sunny Han accused her sister of stealing her BMW.
Gina Han maintained she never intended to kill her sister.
The Associated Press contributed to this report.