ABINGTON (CBS) – Three children and their parents were found dead in an Abington, Monday morning, Plymouth County District Attorney Tim Cruz said. The incident appears to have been a murder-suicide.

A large crime scene was established at the Centre Ave. condo complex. The bodies of 40-year-old Deirdre Zaccardi, 11-year-old Alexis Zaccardi, 9-year-old twins Nathaniel and Kathryn Zaccardi, and 43-year-old Joseph Zaccardi were found inside a townhouse, according to the D.A.

The victims appeared to have been shot, but the medical examiner’s office is working to determine the manner and cause of death.

The D.A. said police were called at 7:30 a.m by a family member who went into the home to pick up a child for school.

The incident appears to be isolated and there is no threat to the public at this time.

Investigators could be seen entering the building wearing protective clothing.

“There’s not a lot of answers to a heck of a lot of questions,” said Cruz.

Police said there were no prior reports of domestic abuse. “There was no indication, no previous calls that would certainly indicate any type of an issue,” said Abington Police Chief David Majenski.

Abington schools said in a letter to the community they are “heartbroken” to learn that a family in town “died unexpectedly.” It said, in part:

There are three young students of this family in our district. At this time, we do not have any other details about what happened. This was an unexpected event, which deeply saddens all of us. This is a tragedy that will affect the entire Abington community. Counseling staff have been made available to support students.

“I think it’s a horrific event for the town of Abington, for the schools and for all the people. I feel bad for the law enforcement personnel and the EMS that showed up, I think it’s a very traumatic event for all of them also. We need to make sure that we can help the people that we can help but for the most part this is an incredibly terrible event, and actually it is what it is, it’s a crime. A crime occurred in that building. Three little children are gone forever as a result of this,” said Cruz.

Members of the family also released a statement on Monday afternoon:

Today our family has suffered an unfathomable loss. As we attempt to make sense of the enormity of this event, we respectfully ask that the media respect our family’s wishes to be left alone as we grieve our tremendous losses in private.

Debbie Welling knows the family well. She brought flowers to the condo complex. They were “super fun and loving and like I said, just a normal family. No signs of any trouble,” she said.

Joe Franey, of Abington, said, “How could anybody do that to anybody, but the children? There’s millions of people who would have taken those children. That’s sad. That’s really sad.”

Deirdre Zaccardi worked for a company called EMI Strategic Marketing. They released a statement that said, in part:

Her welcoming smile, constant enthusiasm, sense of humor and talent for organizing just about anything made her indispensable to the company, and to me personally. Her deep commitment to her children, and the pride she took in their accomplishments, small and large, were part of many conversations. Just last week, she took Wednesday off for the twins’ birthday celebration.