Le, 26, disappeared from Kaiser Permanente Medical Center in Hayward on May 27, 2011. Her body was found in a remote area between Pleasanton and Sunol about four months later.
In his closing argument in Esteban's trial last week, Alameda County Deputy District Attorney Butch Ford said Esteban had planned Le's murder for months.
He played a recording for jurors of a conversation Esteban had with her ex-boyfriend six months before Le was killed.
In the recording, Esteban can be heard telling Scott Marasigan, the father of her 6-year-old daughter, "You deserve to die for your lies, as does she," referring to Le.
Ford alleged that Esteban, 28, of Union City, killed Le, a San Mateo resident who attended Samuel Merritt University in Oakland, because she mistakenly believed Le was having an affair with Marasigan.
Marasigan, 28, testified during the three-week trial that he dated Le for about a month in the spring of 2003 but never had sex with her, although they remained friends after he started seriously dating Esteban later that year.
Marasigan and Esteban had an on-again, off-again relationship for many years but ultimately broke up and Marasigan was awarded custody of their daughter.
Le and Esteban were high school friends in San Diego and both came to the Bay Area to attend college.
Esteban's lawyer, Andrea Auer, admitted that Esteban killed Le but said she was provoked and acted in the heat of passion, and should only be convicted of voluntary manslaughter.
Auer conceded that Esteban had sent dozens of threatening text messages and waited for Le in the Kaiser parking lot for hours until Le went to her car at about 7 p.m. on May 27, 2011, during a break in her classes, and that there was some type of confrontation.
But she said, "You don't know who started it, what was said and what happened."
Ford said it may never be clear how Le died, but said the fact that Le's blood that was found in her own car indicates that Esteban may have approached her from behind and slit her throat.
Although Esteban didn't testify in the trial, Auer said she thinks Esteban never believed Marasigan's repeated statements to her that he never had sex with Le.
Referring to Esteban, Auer said "almost nothing would sway her" from her belief that Marasigan and Le had a sexual relationship.
She said Esteban became suspicious in 2005, when she was pregnant with the couple's daughter and learned that Le had confided in Marasigan that she also was pregnant but planned to have an abortion.
Ford also said if Esteban had been upset with Marasigan and Le in 2005 she had ample time to cool down and consequently didn't act in the heat of passion when she killed Le in May 2011.
"Six years is clearly a long cooling-off period," Ford said.
Stay with ABC7NEWS.COM for updates on thise developing story.