Altemio Sanchez, 49, was arrested earlier this year after DNA evidence linked him to a series of rapes and killings in the Buffalo area.
His arrest stunned all who knew him as a friendly and hardworking father of two from suburban Cheektowaga.
During an appearance in state Supreme Court, Judge Christopher Burns asked Sanchez about each of the three victims.
"I strangled her," he said three times, weeping and barely audible.
Sanchez's wife Kathleen, who has attended all of her husband's court appearances, briefly sobbed as Sanchez pleaded guilty to second-degree murder in each of the deaths. He faces 75 years to life in prison when he is sentenced Aug. 2.
"It is unimaginable to us that someone we have truly loved and respected for so many years could be capable of such violent acts," Kathleen Sanchez and her family said in a statement issued through an attorney, "and we are sincerely sorry and filled with grief for your tragic losses."
Sanchez admitted killing University at Buffalo student Linda Yalem, who was raped and strangled on a bike path near campus in 1990; Majane Mazur, found raped and strangled on a Buffalo street two years later; and Joan Diver, strangled along a bike path last fall.
"The case against him in each of the three homicides was overwhelming," Erie County District Attorney Frank Clark said after the pleas.
Defense attorney Andrew LoTempio said Sanchez wanted to spare his family from a trial and decided to plead guilty after reviewing the DNA evidence against him.
"His decision to do this was mostly based on saving his wife and children from hearing the dirty details of behavior that he's totally ashamed of," LoTempio said.
"The only thing he's remorseful for is that he was caught," Clark responded, "and but for the grace of God, if he wasn't he'd still be out there."
Clark said investigators have tied Sanchez to eight or nine rapes and suspect him in a dozen more dating from the late 1970s to the mid-1990s. After an unexplained 12-year gap, Sanchez struck again, killing Diver on Sept. 29, authorities said.
Another man served 22 years in prison for two rapes that are now tied through DNA to Sanchez. Anthony Capozzi's convictions were erased last month.
Sanchez was arrested after a task force of investigators revisited a victim's report that she spotted her attacker in a shopping mall days after a 1981 rape and jotted down the license plate number of the car he was driving. Police at the time traced the car to Sanchez's uncle, who said the car had not been driven.
Twenty-six years later, the task force interviewed the uncle again. This time, he said his nephew had borrowed the car. Investigators then followed Sanchez and secretly collected his DNA from drinking glasses after he dined at a restaurant with his wife in January. He was arrested two days later.
Even with overwhelming DNA evidence, Clark said, some of Sanchez' acquaintances insisted authorities had the wrong man. Neighbors described him as an attentive father and husband who threw neighborhood parties and impressed all with his carefully tended lawn and flowers.
"The fact that somebody could engender such loyalty and trust and even affection out of some and such fear and hatred out of another is an amazing thing to me," Clark said.