Investigators say the father-in-law survived and found the victims Saturday morning.
WOODBRIDGE, VA — A 35-year-old woman is believed to have fatally stabbed her 2-year-old son, her husband and her mother-in-law inside a Woodbridge townhouse before taking her own life, police in Prince William County said Monday.
The deaths, discovered Saturday morning, have left relatives and neighbors grappling with what investigators called a sudden, devastating family tragedy. Police said a weapon was recovered and autopsies found all four died from knife-related injuries. Authorities have not released a motive and said they are examining possible factors, including mental illness and whether drugs or alcohol played a role.
Officers were sent to the 3400 block of Vale Court at about 8:05 a.m. Saturday after a family member called 911, police said. Inside the home, investigators believe Ziyi Lu attacked three relatives: her mother-in-law, Kegang Xie, 69; her husband, Danxiong Gao, 40; and the couple’s 2-year-old son. Police did not release the child’s name because of his age. Lu was also found dead, and investigators said the scene appeared to be a murder-suicide.
Prince William County police Col. Peter Newsham said the first responders arrived to what he described as a nightmare for a family and for the officers tasked with entering the home. “We don’t know the exact cause or the motive in this case, but just to see a family destroyed like this is horrific,” Newsham said in an interview after the deaths were discovered. Police said the surviving relative is cooperating with detectives as they piece together what happened in the hours before the 911 call.
Investigators said the only close family member known to have survived was Gao’s father, who police said was in the basement during the killings. He later found the four family members dead upstairs and called for help, authorities said. Newsham said the man was distraught but has been cooperative with investigators. Police said they recovered the weapon believed to have been used in the stabbings and are waiting on additional investigative findings as they work to establish a clearer timeline.
Police released the names of the adults on Monday as they provided an update on the investigation. Authorities said the adults had added Americanized first names to their Chinese names, and friends and neighbors also referred to Gao by an English name. In interviews, people who said they knew the family described them as quiet, friendly and hard-working, a picture that made the violence difficult to understand for those living nearby.
A former neighbor, Mike Giampa, said he met Gao in 2018 and stayed in touch after they moved. Giampa said Gao ran a tax accounting business and grew up in Fairfax County. He said he went to police headquarters after hearing about the deaths to offer any information he could, and later was able to see Gao’s father. Giampa described a grieving parent overwhelmed by loss and confusion, then said he brought the man home so he would not be alone.
Other neighbors said the family kept to themselves but exchanged greetings and small gestures. One next-door neighbor told local reporters he had seen Gao the night before the killings and said nothing seemed unusual. A nearby resident, Edie Modlin, said the deaths were heartbreaking, especially the loss of the toddler. Residents said they watched police activity outside the townhouses as word spread that four people had been found dead inside a home on the block.
Police said they had not previously been called to the home for any reported issues, a detail that can complicate efforts to understand what led up to the violence. Investigators said they are exploring whether a mental health issue may have been involved and are also considering the possible influence of drugs or alcohol. Authorities emphasized that no single explanation has been determined and said the investigation is in its early stages, with detectives relying on physical evidence, interviews, and available records.
In cases like this, investigators typically try to reconstruct the final day through phone data, messages, surveillance footage where available, and interviews with family members and acquaintances. Police have not said whether they have identified any warning signs, arguments, or recent changes that might help explain the attack. They also have not described where inside the townhouse the victims were found or whether anyone attempted to flee or seek help.
Newsham said the deaths were hard on the community and on the officers who responded. He said investigators are focused on confirming the sequence of events and understanding why the attack occurred. Police have not announced any pending criminal charges because the suspected assailant is dead. Instead, the case will likely be closed through an investigative determination by police and the medical examiner once the review of evidence is complete.
The killings occurred in Woodbridge, a large suburban community in Prince William County about 20 miles south of Washington, known for dense neighborhoods of townhouses and single-family homes. Vale Court sits in a residential area where homes share walls and neighbors often hear one another’s daily routines. Several residents said the heavy police presence Saturday morning, along with the later confirmation that a child was among the dead, left people shaken.
Police said autopsies confirmed the manner and cause of death for the four family members as knife-related injuries. Authorities did not specify when the autopsies were performed, but said results supported the initial belief that the deaths were the result of a domestic attack followed by suicide. Investigators said they recovered the suspected weapon, which may help them confirm how the attack unfolded and whether there were multiple instruments involved.
Detectives also are expected to review whether there were any recent calls for service in the broader neighborhood, reports from schools or child care providers, or contact with health care systems that could shed light on the family’s circumstances. Police have not said whether the family had recently moved to the home or whether any relatives from outside the area were expected to arrive. They also have not described the toddler’s routine, including whether the child attended day care.
Friends said Gao worked in tax preparation and accounting, a role that often involves long hours during the early months of the year. Police did not discuss his work schedule or whether he had been home overnight. Authorities also have not said what Xie was doing in the home or whether she lived with the family full time. Investigators said the woman killed in the attack was Lu’s mother-in-law, indicating she was Gao’s mother.
Police did not release details about Lu’s background, employment, or medical history. They have not said whether she had ever been evaluated for mental health concerns or whether she was receiving care. Investigators also have not disclosed whether the household had any prior protective orders, separation plans, or domestic calls that might indicate escalating conflict. Newsham said police had no prior record of being called to that address for disturbances.
In the days after the deaths, police said they were continuing interviews and gathering records to understand what happened before the 911 call. Investigators often look at recent travel, financial stress, family disputes, and other possible pressures, but officials cautioned that such factors can be complex and not always documented in a way that makes them clear quickly. Police said they do not yet know what triggered the violence.
Residents on and around Vale Court said the incident changed the feel of the neighborhood overnight. Some described seeing patrol cars, detectives and crime scene tape early Saturday, followed by a quiet stillness as the investigation continued. People who said they had spoken with the family in passing described them as polite and ordinary. Several said they struggled to reconcile that image with the details released by police.
Authorities said the investigation will proceed as a death investigation rather than a prosecution. That process includes finalizing autopsy reports, documenting the scene, collecting and analyzing evidence, and writing a comprehensive report summarizing findings. Police said they expect to continue speaking with relatives and others who may have knowledge of the family’s recent circumstances. Investigators also are expected to review any digital evidence that could clarify timing and intent.
For now, police said their focus remains on confirming what happened inside the townhouse and providing answers to surviving family members. Newsham said the deaths were a severe loss for everyone connected to the family and for the community that watched events unfold from outside. He said investigators will share additional details when they can do so without compromising the inquiry.
The case remained under investigation Monday, with police saying the next milestone will be the completion of the remaining investigative reviews and final reports from the medical examiner. Authorities said they will release more information if new, confirmed details emerge.
Author note: Last updated February 24, 2026.