Dressed in a striped uniform, Matthew, 33, was escorted into Charlottesville's Albemarle County Circuit court and entered a guilty plea for the murders of University of Virginia student Hannah Graham, 18, and Virginia Tech student Morgan Harrington, 20.
He also pleaded guilty to abduction with the intent to defile in both cases.
In exchange for his guilty pleas, he has been sentenced to four consecutive life sentences, the statutory maximum for each of these counts, said Albemarle County Commonwealth's Attorney Robert Tracci in a statement.
Matthew would not be eligible for geriatric release under terms of the agreement.
The former cab driver and hospital worker is charged with abduction with the intent to defile and first-degree murder in the deaths of the students. Matthew could have faced the death penalty if he had been convicted at trial.
He is already serving three life terms in prison for sexual assault and attempted murder in Fairfax County in 2005.
"This plea arrangement brings finality," Morgan's mother, Gil Harrington, tells PEOPLE. "It’s a punctuation point that the judicial process is finished.
"We're grateful for that as well as the fact that a guilty plea carries with it accountability. It validates the injury that was done to our daughter."
In an emotional statement to the court, Morgan's father, Dan Harrington, said, "Our little girl, Morgan was killed by Jesse Matthew. How can that be? The brutality and intentionality of Morgan's murder pierces our every day, and will continue to do so until we join her.
Addressing Matthew, he said, "How could you? Why would you?"
Talking about the good he and his wife have done in their daughter's name since her death, including building a school in Africa in her honor, he said, "Yes, we have suffered and we are wounded but we have not let Jesse Matthew destroy or define us."
As part of the plea agreement, Matthew waives his right to early, conditional release or parole. He also waives any right to appeal or revoke this agreement. The Commonwealth can re-indict this charge without time limitation should Matthew violate terms of the plea.
Said Tracci, "This resolution serves the interests of justice by ensuring the defendant will never again pose a threat to public safety. It is consistent with the wishes of the Graham and Harrington families, and provides a measure of legal finality in cases that would have been subject to highly public trials and protracted appellate review.
"The agreement can be attributed to the outstanding work of law enforcement personnel and volunteers who made Hannah and Morgan’s cause their own."
Matthew’s lawyer, Douglas Ramseur, read a statement from the defendant" "He's very sorry for what happened," Ramseur said. "He loves his family very much."
Reuters / Landov
Hannah Graham: Video Shows Matthew Following HerGraham disappeared on Sept. 13, 2014, after having dinner with friends and attending two parties.
Surveillance video showed her running through the streets of Charlottesville and wandering in a downtown pedestrian mall near the university. She texted friends at 1:20 a.m. saying she was lost trying to find a party, police have said.
Video showed Matthew following her as she ran past stores and restaurants in the seven-block outdoor pedestrian mall, police said.
Later that night, she was seen on video leaving a restaurant with Matthew, who had his arm around her. He was the last person to be seen with Graham, according to authorities.
After a massive, five-week search, her remains were found on October 18 on a vacant lot in Albemarle County, about 12 miles from Charlottesville – and 6 miles from a farm where Harrington's remains had been found on January 26, 2010.
Soon after Graham vanished, police searched Matthew's apartment and named him a person of interest in her disappearance. He fled and was arrested on a beach in Galveston, Texas. He was charged with abduction with intent to defile.
After his arrest, police were able to retrieve a DNA sample from him, which showed that he was forensically linked to a 2005 sexual assault in Fairfax County, according to authorities.
The DNA evidence in the Fairfax sexual assault then connected Matthew to Harrington's murder, authorities have said.
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Morgan Harrington: A Family’s Mission to 'Help Save The Next Girl'Harrington vanished while attending a Metallica concert at the University of Virginia on October 17, 2009. During the show, Harrington told friends that she was going to the restroom, her mother, Gil Harrington told PEOPLE.
When her friends called her because they were looking for her, she told them she was locked out of the arena because of its "no re-entry" policy and would find her way home.
She was last seen at around 9:30 p.m. on Charlottesville's Copeley Road Bridge, police said.
Her purse and cell phone were found the next day in one of the arena's overflow parking areas.
In April 2010, authorities confirmed that forensic testing found that the t-shirt Harrington was wearing the night she disappeared was the same one that was found in November 2009 – the month following her disappearance – outside a Charlottesville apartment building.
When Harrington's remains were found in a hayfield three months later, her mother vowed to help catch the man who took her daughter's life.
Harrington and her husband, Dan, and a small army of volunteers distributed hundreds of flyers of a composite sketch of the suspect. They hung posters all over Charlottesville and displayed the suspect's sketch on billboards.
Harrington and her husband even started an organization Help Save The Next Girl, a nationwide non-profit aimed at trying to prevent crimes against young women by promoting personal safety.
"We never let up on him," Harrington told PEOPLE. "I moved heaven and earth to stay on top of him and stop him."
After six long years, Harrington said she felt "vindicated" when she and her husband sat in court just feet away from Matthew at his September 2015 arraignment on charges of first-degree murder and abduction with the intent to defile in the disappearance and death of their daughter.
When Matthew got up to leave court – led by officers and in chains, "He looked long and hard at me and Dan," she said. "It was like a predator to hunter – but we were the ones who had hunted him down."
Three Life SentencesOn October 5, 2015, a Fairfax County circuit court judge handed down three life sentences to Matthew for the 2005 attempted murder, sexual assault and abduction of the Fairfax County woman.
Matthew had entered an Alford Plea for the violent attack, when he grabbed the then-26-year-old woman and dragged her to a nearby wooded area. (An Alford Plea is when a defendant does not admit guilt, but acknowledges that there is enough evidence for a conviction.)
"The violence of these offenses was extreme," said Judge David Schell.
Matthew's mother screamed out "No!" as the sentences were handed out and told the judge to "rot in hell," the Associated Press reported. She refused to budge as deputies tried to take her from the courtroom. Matthew, under escort, left the room quietly.
Matthew's family had asked for mercy for him, with the defense arguing that Matthew was a victim of sexual abuse as a child. But the prosecutor, Raymond Morrogh, told WTVR that Matthew's alleged past is no excuse.
"If he was, in fact, abused, he should know better than anyone the pain associated with that," Morrogh said after the sentencing last fall. "And for him to treat [the victim] in the manner he did was despicable and violent and I'm glad he got three life sentences."
Matthew had been accused of sexual assault in 2002 and 2003 at Liberty University and Christopher Newport University. Both cases were dropped when the women declined to press charges.