Widower of Arizona county attorney shoots dead his girlfriend and her mom before turning the gun on himself during an argument at a Christmas Eve party

The widower of a top prosecutor in Arizona fatally shot his new girlfriend and her mother at a Christmas Eve party before turning the gun on himself, authorities said.

David De Nitto, who was married to Maricopa County Attorney Allister Adel until her death at age 45 on April 30, 2022.

After her death, the Wells Fargo financial advisor, 47, began dating Molly Domini-Cash, a local real estate agent in Phoenix.

Around 11:30 p.m., during a Christmas Eve gathering with her family at a home near Central Avenue and Bethany Home Road, the relationship turned deadly. De Nitto became involved in a heated argument that raged until he grabbed a gun and shot and killed Domini-Cash, 47, and her 83-year-old mother Cynthia Domini, police said.

Both women were rushed to the hospital but died from their injuries, and De Nitto was later found dead of a self-inflicted gunshot wound.

A poignant photo shows all three at a family gathering in October, along with Domini-Cash's 26-year-old son and De Nitto and Adel's two young boys.

Now orphaned, Adel and De Nitto's two sons must come to terms with their father's heinous crimes.

'It is impossible to understand a tragedy like this. Words cannot adequately express the flood of grief,” said Adel's successor Rachel Mitchell.

“I ask the community to join me in praying for the affected families and especially for the children of Allister. I also ask that the community surround the families with love and kindness.”

Domini-Cash was a real estate agent at North&Co and, like Adel, a passionate Arizona Cardinals fan whose son was a football star at Sunnyslope High School in Phoenix.

Domini-Cash lost her eldest sister Lisa, a teacher, to cancer and a stroke in March, and her elderly father not long before.

“I don't know how we will get through this…I really have no idea…but I know we will do it the way you would want us to,” she wrote of her sister at the time.

De Nitto was named the 144th best wealth advisor in Arizona by Forbes in April. He specialized in asset and pension planning.

Adel was rushed to hospital on the night of the 2020 election, where she had to undergo emergency surgery due to a brain haemorrhage. Nine days earlier, she fell and hit her head, causing a blood clot in her brain that went unnoticed at the time.

She was in hospital for two months and underwent a second operation in January 2021, only returning to work in February.

Adel resigned amid criticism of her performance, including the dismissal of 180 misdemeanor cases because charges were not filed before the statute of limitations expired.

She also controversially accused several Black Lives Matter protesters as gang members in October 2020, only dropping the charges after a local news investigation.

Adel claimed her brain injury “affected her ability to investigate the case and understand the evidence behind the allegations.”

This contrasted with her office declining to charge police officers involved in the shooting of unarmed 28-year-old Dion Johnson a month earlier.

She was also scrutinized as to whether a recognized alcohol abuse problem had affected her ability to do the job.

Adel admitted her psychological issues on September 10, 2021, and asked for patience from her constituents as she tried to “improve herself.”

“I made the decision to seek treatment for anxiety and to address unhealthy coping behaviors, including an eating disorder and alcohol use,” she said, saying she tried to tackle it on her own but wasn't able to managed to tackle this.

“I know that if I want to be successful in my recovery, I have to be honest and hold myself accountable.

“I have a challenging journey ahead of me to do better and be better for my friends, family, staff, this community and ultimately myself. I hope you will find it in your heart to give me the opportunity.

“None of us are born perfect and life brings unexpected challenges. We all have obstacles that we face in life and this is what makes us human.

'I admit that I am far from perfect. This is a private trip for most, but as an elected official I know there is a different standard being met.”

The month before, she had checked into a drug rehab center in California for the same problems, but admitted to having had two consecutive alcohol relapses.

Adel faced calls to resign, which she resisted for months until she finally resigned in March 2022, dying the following month.

This came after five of her top accusers wrote a letter demanding her resignation, which “raised ethical questions about her sobriety, her long absences from work and her judgment.”

Adel's cause of death was never released and her family would only say that she died of non-specific “health complications.”