Seven people, including four children, were killed in a shooting near the Margaret River in western Australia on Friday, The Guardian reported. This is the country’s worst mass shooting since the Port Arthur massacre in 1996.

The police found the bodies of Katrina Miles, her parents Cynda and Peter Miles, who own the property, and her four children, around 5.30 am local time (3 am Indian Standard Time) on Friday, reported Perth Now.

Police are treating the incident as a murder-suicide and are not looking for suspects. Two firearms were found on the property, but it is not known who began the massacre.

Western Australia Police Commissioner Chris Dawson said all the victims appeared to be residents of the property, which comprises a house and a shed that had been converted into living quarters. He added that the victims had gunshot wounds and bodies of five victims – the four children and one adult – were found inside the shed. Two other bodies were found outside.

“This devastating tragedy will no doubt have a lasting impact on the families concerned, the whole community and in particular the local communities in our south-west,” Dawson said, according to The Guardian.