still struggling with impact/significance

An estranged daughter and her husband start a family shoot out at her parents’ mobile home in rural Pennsylvania leaving everyone except the woman’s father dead. John Frew allegedly shot and killed attackers Josephine and Jeffrey Ruckinger before realizing that Josephine was his own daughter. Frew’s wife Roberta and son John Jr. were also killed in the shootout. The investigation is still ongoing, however authorities believe the Ruckingers arrived armed with a pistol with intentions of murdering the family. Josephine had been separated from the family for about 20 years following a feud, a family member told the Associated Press. Investigators say the family was watching TV after dinner when there was a knock. Josephine allegedly shot her mother directly at the door, and Jeffrey then killed John Frew Jr., as he reached for a weapon, before his father John Frew Sr. shot both assailants.
This story is significant because 4 people were deliberately killed and happened to be family members
The impact of this story same as significance?

Also if you see problems grammatically with how I summarized the article, feel free to point those out..

Thanks

I think the impact is the sheer emotion (entertainment value?) of reading about this bizarre event.

Your summary is o.k., except for this run on sentence.

The investigation is still ongoing, however authorities believe the Ruckingers arrived armed with a pistol with intentions of murdering the family.