Postpartum mental health condition likely a factor in murder-suicide of Dr. Krystal Cascetta, sources say

SOMERS, N.Y. -- There's new information in that tragic murder-suicide involving a Westchester doctor and her 4-month-old daughter. 

We've learned the gun used was properly registered to the doctor's husband, and sources tell CBS2's Tony Aiello a postpartum mental health condition is likely a factor. 

Postpartum mental health conditions impact an estimated 20% of new moms, and investigators believe postpartum depression, or more severe postpartum psychosis, was a factor in the death-by-suicide of cancer doctor Krystal Cascetta after police said she shot and killed her 4-month-old baby girl at their home in Somers, Westchester County. 

"It was absolutely heartbreaking to hear this news," Adriana Pentz said. 

• Related: Apparent murder-suicide involving prominent Mt. Sinai Hospital oncologist rocks Westchester County town of Somers

Pentz is an advocate working to spread awareness of postpartum mental health. She experienced postpartum depression a decade ago after the birth of her first child. 

"I started to withdraw from my surroundings. I was feeling very nervous. I became very worried about my daughter," Pentz said. 

Cascetta was a highly educated doctor. Experts said postpartum mental health conditions impact women at every level of education and income. 

"Really does not discriminate based on education, or age, or how badly a woman wants a baby or wants to be a mom," Dr Catherine Daniels of Westchester Medical Center said. 

Daniels, a psychiatrist, said it's important to surround new moms with love and support, and to be aware of behaviors that seem out of sync. 

"With an eye towards women seeming very anxious and concerned about the welfare of the baby, women doubting their own ability to adequately care for the baby, and a real sort of sadness and disinterest and withdrawal," Daniels said. 

Just this week, the FDA approved the first drug specifically to treat postpartum depression - zuranolone. 

"I think what's so significant about this - it brings attention to and progress to this area of treating postpartum depression, which gives all of us a lot of hope," Pentz said.