In a tragic turn of events, an 80-year-old artist, her two sons, and her daughter-in-law were discovered dead early Tuesday morning in what authorities suspect to be a triple murder-suicide. The incidents took place across two upscale neighborhoods in the Seattle suburbs.

Authorities reported that Danielle Cuvillier, aged 80, and her 45-year-old son, Mackenzie P. Williams, were found deceased at a residence on Mercer Island, located just seven miles from Seattle. This information was shared by local police via a Facebook update.

Later the same day, during a welfare check, police discovered the bodies of a woman in her 40s and a man in his mid-30s at a home in Issaquah, situated 17 miles from Seattle. This was confirmed in a Facebook post by the Issaquah Police Department.

Commander Jeff Magnan from the Mercer Island Police Department revealed that his office had alerted the Issaquah police about the deaths of Danielle and Williams and requested a welfare check on Danielle’s 34-year-old son, Dominick Cuvillier, and Williams’ spouse, as reported by the Seattle Times and KIRO 7.

Dominick was identified as one of the victims found in the Issaquah residence, according to Danielle’s attorney speaking to KIRO 7. Neighbors corroborated that the other unidentified victim was Williams’ wife.

Danielle and Williams’ deaths are being investigated as a homicide and suicide, though police haven’t identified the shooter.

The mother was a “dedicated artist” with an interest in photography, sharing her work on Instagram over the years.

Authorities recovered four firearms inside the Mercer Island home and found a fifth in a car on site, according to the Mercer Island Police Department.

The Issaquah deaths are being investigated as homicides, according to KOMO News. Authorities noted that both victims had been shot, and there was no sign of forced entry.

The gruesome deaths came after more than a year of intense conflict between Danielle and Williams about the artist’s younger son’s care, according to court documents obtained by the outlets.

The 34-year-old was diagnosed with Angelman syndrome, a rare genetic disorder that causes severe developmental delays and requires extensive round-the-clock care.

Dominick lived with his parents until his father died in 2018. After that, Williams stepped in and arranged a shared caregiving regimen for him with their mother.

Williams accused Danielle of physically and emotionally abusing his disabled brother in a King County court declaration, which Danielle denied, the outlets reported.

In January 2025, Williams met with a lawyer and started working towards assuming power of attorney, with his brother’s consent, so he could be solely responsible for his sibling’s care.

Danielle then accused her younger son of being “unduly influenced” to relinquish control to Williams, the Seattle Times reported.

The matriarch was later charged with fourth-degree assault after a tiff with Williams at the Mercer Island home, which she refused to let him enter.

Danielle later filed a petition for a protection order against Williams on behalf of her younger son. In the order, she claimed Williams’ “behavior has been unpredictable and aggressive lately” and highlighted the startling number of firearms in his home, the outlet reported.

Williams confessed to having 53 firearms in his home, which he surrendered, according to a separate document.

The protection order was approved and reissued three more times, but was terminated in early December.

In August, Danielle and Williams agreed to have Dominick live with his mother, but permitted visitations on Sundays and Mondays, plus one weekend a month. They agreed to only communicate with each other over text and email so that Dominick wouldn’t be caught between their squabbles.

Danielle was also named as his sole guardian and conservator.

The King County medical examiner’s office will determine the cause and manner of all the victims’ deaths.