Police say a suspected mass killer confessed to killing four family members before turning the gun on himself in a disturbing Facebook post.

Brandon Taylor Cole-Skogstad, 29, is accused of shooting his aunt, uncle, two young cousins, and the family dog on Tuesday at their Minnesota home.

According to officials, he shot his family while they slept after posting a disturbing statement on Facebook that he had taken “the utterly horrible decision.”

Rian Barry, 44, her husband Sean, 47, and their kids Shiway, 12, and Sadie, nine, have been identified as the victims.

Cole-Skogstad wrote on Facebook an hour before police suspect the murder occurred that he had “suffered many years of mental illness,” but that he nearly never sought treatment since he didn’t “deserve it.”

Survivor family members, as well as Duluth Police Chief Mike Tusken, verified Cole-Skogstad confessed on Facebook, according to Fox 21.

The alleged killer went on to state in the post that he wishes he could go back in time and “ignore the venom thrown at me by peers for so long.”

“Sweet and beyond heavenly,” Cole-Skogstad said of his two little cousins.

“I have no idea how I got to this choice,” the post adds, “but I do know this.” If there is a God in heaven, I pray that he blesses my family with the most pleasant afterlife conceivable.

“Whether or not I pray for forgiveness, whether God can actually forgive me.” Whether or not I believe I am deserving, all I want is that they apologise to everyone. I sincerely hope that I will be able to accept feelings of love from others.

The Facebook post has subsequently been removed.

After relatives claimed Cole-Skogstad was in a crisis, police arrived at the family’s house in East Hilllside, Duluth, on Wednesday to conduct a welfare check.

They discovered Cole-Skogstad in the midst of a mental health crisis, and a confrontation followed when they discovered he had firearms.

After hearing a gunshot, a SWAT squad entered the house and discovered the four victims’ bodies, as well as Cole- Skogstad’s.

The occurrence, according to Chief Tusken, was a “unimaginable catastrophe” that “is very, very terrible for us, that causes us to have heavy, heavy hearts.”

A GoFundMe for the family says: “They were a truly special family who impacted the lives of so many of those around them. They leave behind their mothers, fathers, sisters, brothers, nieces, nephews and many many friends. “Family are not prepared for this horrible tragedy.”