Puente was born Dorothea Helen Gray on January 9, 1929 in Redlands, California, to Trudy Mae (Yates) and Jesse James Gray. Her father died of tuberculosis in 1937 when she was eight years old, and her mother died in a car accident the following year. She was sent to an orphanage.
In 1945, Gray was married for the first time, at the age of 16, to a soldier named Fred McFaul, who had just returned from the Pacific Theater of World War II. Puente had two daughters between 1946 and 1948, but she sent one to live with relatives in Sacramento and gave the other up for adoption. She became pregnant again in 1948, but suffered a miscarriage. In late 1948, McFaul left her.
Gray was sentenced to a year in jail for forging checks; she was paroled after six months. Soon afterwards, she was impregnated by a man she barely knew and gave birth to a daughter, whom she gave up for adoption. In 1952, she married a Swede named Axel Johanson, and had a turbulent 14-year marriage.
In 1960, she was arrested for owning and managing a brothel and was sentenced to 90 days in the Sacramento County Jail. After her release, she was arrested again, this time for vagrancy, and sentenced to another 90 days in jail. Following that, she began a criminal career that over time became more serious. She found work as a nurse's aide, caring for disabled and elderly people in private homes. In a short time, she started to manage boarding houses.
She divorced Johanson in 1966 and married Roberto Puente, a man 19 years her junior, in Mexico City. The marriage lasted two years. Shortly after it ended, Dorothea Puente took over a three-story, 16-bedroom care home at 2100 F Street in Sacramento; she would later rent an upstairs apartment at 1426 F Street. Puente got married for the fourth time in 1976 to Pedro Montalvo, who was a violent alcoholic. This marriage lasted only a few months, and Puente started to spend time in local bars looking for older men who were receiving benefits. Puente forged their signatures to steal their money. She was caught and charged with 34 counts of treasury fraud, for which she received probation.
Puente's reputation at the F Street boarding house was mixed. Some tenants resented her stinginess and complained that she refused to give them their mail or money; others praised her for small acts of kindness or for her generous homemade meals. Her motives for killing tenants were financial, with police estimates of her ill-gotten income totaling more than $5,000 per month. The murders began shortly after Puente began renting out space in the home at 1426 F Street. In April 1982, 61-year-old friend and business partner Ruth Monroe began living with Puente in her upstairs apartment, but soon died from an overdose of codeine and acetaminophen. Puente told police that the woman was very depressed because her husband was terminally ill. They believed her and ruled the incident as a suicide.
A few weeks later, the police were back after a 74-year-old pensioner named Malcolm McKenzie (one of four elderly people Puente was accused of drugging) accused Puente of drugging and stealing from him. She was convicted of three charges of theft on August 18, 1982, and sentenced to five years in jail, where she began corresponding with a 77-year-old retiree living in Oregon, named Everson Gillmouth. A pen-pal friendship developed, and when Puente was released in 1985 after serving just three years of her sentence, he was waiting for her in a red 1980 Ford pickup. Their relationship developed quickly, and the couple was soon making wedding plans. They opened a joint bank account and paid $600-a-month rent for the upstairs apartment at 1426 F Street in Sacramento.
In November 1985, Puente hired handyman Ismael Florez to install some wood paneling in her apartment. For his labor and an additional $800, Puente gave him a red 1980 Ford pickup in good condition, which she stated belonged to her boyfriend in Los Angeles who no longer needed it. She asked Florez to build a box 6 feet by 3 feet by 2 feet to store "books and other items". She then asked Florez to transport the filled and nailed-shut box to a storage depot. Florez agreed, and Puente joined him. On the way, however, she told him to stop while they were on Garden Highway in Sutter County and dump the box on the river bank in an unofficial household dumping site. Puente told him that the contents of the box were just junk. On January 1, 1986, a fisherman spotted the box sitting about three feet from the bank of the river and informed police. Investigators found a badly decomposed and unidentifiable body of an elderly man inside. Puente continued to collect Everson Gillmouth's pension and wrote letters to his family, explaining that the reason he had not contacted them was because he was ill. She maintained a "room and board" business, taking in 40 new tenants. Gillmouth's body remained unidentified for three years.
Puente continued to accept elderly tenants, and was popular with local social workers because she accepted "tough cases", including drug addicts and abusive tenants. She collected tenants' monthly mail before they saw it and paid them stipends, pocketing the rest for "expenses". During this period, parole agents went and visited Puente, who had been ordered to stay away from the elderly and refrain from handling government checks, a minimum of fifteen times at the residence. No violations were ever noted.
Suspicion was first aroused when neighbors noticed the odd activities of a homeless alcoholic known only as "Chief", whom Puente stated she had "adopted" and made her personal handyman. Puente had Chief dig in the basement and cart soil and rubbish away in a wheelbarrow. At the time, the basement floor was covered with a concrete slab. Chief later took down a garage in the backyard and installed a fresh concrete slab there as well. Soon afterward, Chief disappeared.
On November 11, 1988, police inquired after the disappearance of tenant Alberto Montoya, a developmentally disabled man with schizophrenia whose social worker had reported him missing. After noticing disturbed soil on the property, they uncovered the body of tenant Leona Carpenter, 78. Seven bodies were eventually found, and Puente was charged with a total of nine murders, convicted of three and sentenced to two life sentences.
During the initial investigation, Puente was not immediately a suspect, and was allowed to leave the property, ostensibly to buy a cup of coffee at a nearby hotel. Instead, after buying the coffee, she fled immediately to Los Angeles, where she befriended an elderly pensioner she met in a bar. The pensioner, however, recognized her from police reports on television and called the authorities.
Her trial was moved to Monterey County, California, on a change of venue motion filed by her attorneys, Kevin Clymo and Peter Vlautin III. The trial began in October 1992 and ended a year later. The prosecutor, John O'Mara, was the homicide supervisor in the Sacramento County District Attorney's office.
O'Mara called over 130 witnesses. He argued to the jury she had used sleeping pills to put her tenants to sleep, then suffocated them, and hired convicts to dig the holes in her yard. Clymo concluded his closing argument by showing a picture commonly used in psychology that can be viewed in different ways and saying "Keep in mind things are not always as they seem." The jury deliberated over a month and found Puente guilty of three murders. The jury was deadlocked 11 to 1 for conviction on all counts, and the lone holdout finally agreed to a conviction of two first degree murder counts including special circumstances, and one second degree murder count. The penalty phase of the prosecution was highlighted by her prior convictions introduced by O'Mara.
The defense called several witnesses that showed Puente had a generous and caring side to her. Witnesses, including her long-lost daughter, testified how Puente had helped them in their youth and guided them to successful careers. Mental health experts testified of Puente's abusive upbringing and how it motivated her to help the less fortunate. At the same time, they agreed she had an evil side brought on by the stress of caring for her down-and-out tenants.
O'Mara's closing argument focused on Puente's acts of murder:
"Does anyone become responsible for their conduct in this world? ...These people were human beings, they had a right to live-they did not have a lot of possessions-no houses-no cars-only their social security checks and their lives. She took it all... Death is the only appropriate penalty."
Kevin Clymo responded by evoking Dorothea the child and caregiver. Peter Vlautin addressed the jurors in confidential tones, contrasting with O'Mara's shouting:
"We are here today to determine one thing: What is the value of Dorothea Puente's life? That is the question. Does she have to be killed?" Vlautin spoke gently about Puente's childhood touching on the traumatic aspects that shaped her life and urged the jurors to see the world through her eyes. "You have heard of the despair which was the foundation of her life, the anger and resentment...If anyone in the jury room tells you it was not that bad, ask them would you want that to happen to yourself? Would you want that to happen to your children? ... I am led to believe if there is any reason for us to be living here on this earth, it is to somehow enhance one another's humanity, to love, to touch each other with kindness, to know that you have made just one person breathe easier because you have lived. I submit to you ladies and gentlemen that is why these people came to testify for Dorothea Puente ... I think you can only truly understand why so many people testified and asked you to spare Dorothea's life only if you have ever fallen down and stumbled on the road of life and had someone pick you up, give you comfort, give you love, show you the way. Then you will understand why these people believe Dorothea's life is worth saving. That is mitigating. That is a human quality that deserves to be preserved. It is a flame of humanity that has burned inside Dorothea since she was young ... That is reason to give Dorothea Puente life without the possibility of parole."
Another juror said "Executing Puente would be like executing mine or your Grandma."
After several days of deliberations, the jury was deadlocked 7–5 for life. The judge, Michael J. Virga, declared a mistrial when the jury said further deliberations would not change their minds. Under the law, Puente received life without the possibility of parole. She was incarcerated at Central California Women's Facility (CCWF) in Chowchilla, California. For the rest of her life, she maintained her innocence, insisting that all her tenants had died of "natural causes".
She died on March 27, 2011 in prison in Chowchilla at the age of 82 from natural causes.
Puente has been featured on numerous true crime television shows including Crime Stories, Deadly Women, and A Stranger In My Home.
In 1998, she began corresponding with Shane Bugbee. The result was Cooking with a Serial Killer (2004), which included a lengthy interview, almost 50 recipes, and various pieces of prison art sent to Bugbee by the convicted murderer. Jodi Picoult mentions Puente's crimes and cookbook in her novel House Rules.
The house at 1426 F Street was included in the 2013 home tour held by the Sacramento Old City Association. It was then the subject of the 2015 documentary short The House Is Innocent and was again opened to tours for one day in conjunction with a local film festival's showing of the film. A 2017 episode of the series Ghost Adventures also had Zak Bagans, his ghost hunting team, and a medium visit Puente's home.