It was so simple.

Matthew Lindquist, a 21-year-old Connecticut man, wanted to exchange his dad’s guns for drugs, so he came up with a plan to fake a robbery at his parent’s house, intending to blame it on “two black guys,” according to an arrest affidavit unsealed Tuesday. But the plot went horribly awry—and Lindquist and his parents ended up dead.

It all began days before Christmas, when Lindquist made a deal with another man, Sergio Correa, promising to give him his dad's guns in exchange for drugs, according to the 17-page arrest affidavit. Together, the pair would fake the robbery, with Correa tying up Matthew to make it look real, the affidavit says.

“If u pull up street from my house and give me a stack I’ll show you right where safe is,” Matthew Lindquist told Correa in a text on December 19, according to court records.

But moments before executing the plan, Lindquist got “panicky and fidgety” and tried to run away, Correa’s non-biological “sister” Ruth, who was with the two men that night and ultimately charged in the killings, told police. That’s when Sergio Correa hit Lindquist on the back of the head with a machete—then gave his knife to Ruth Correa, who told cops she stabbed Lindquist about 10 times, according to the affidavit. The duo went on to kill Kenneth and Janet Lindquist, steal their belongings, and burn their Griswold home to the ground, Ruth Correa told investigators in May.

Correa was arrested on May 12 and charged with murder, first-degree arson, home invasion, and first-degree robbery in a New London Superior Court, The Washington Post reported. The 23-year-old claimed that Sergio Correa, who has not been charged in the case, is to blame for most of the violence. He’s currently in prison for an unrelated probation violation, and his lawyer, William Gerace, maintains his 26-year-old client was not involved in the scheme, according to the Hartford Courant.

Ruth Correa told police that after stabbing Lindquist and leaving him for dead, they made their way into the house but were surprised by the presence of his 56-year-old father, Kenneth Lindquist. Sergio Correa quickly hit him with a baseball bat, Ruth Correa claimed in the affidavit. Janet, who was 61 years old, later approached them, but Ruth Correa took her to a bedroom, saying she “did not have to see this,” according to the affidavit.

Correa told investigators she began to loot the home—with her brother grabbing the guns—and took the items to the getaway car. During one of her trips back into the home, she witnessed Sergio Correa choking Janet Lindquist with a string or a rope until she stopped moving, the affidavit says. When Ruth Correa went back into the home a little later, Sergio was strangling the woman again with his foot pressed into her back—and said he saw Lindquist trying to reach for her phone, the Post reported.

Before leaving, Sergio Correa lit an exercise ball on fire after directing his sister to pour flammable liquid throughout the home, according to the affidavit.

Ruth Correa told investigators she did not know Kenneth Lindquist was killed but saw his body in the hallway. Lindquist died of “homicidal violence including multiple skull fractures and traumatic brain injuries,” while Janet Lindquist died of “homicidal violence including blunt impact injuries to the head,” along with smoke injuries, according to the Courant.

Ruth is scheduled to appear in court on June 6, the Courant reported.

Friends and family of Matthew Lindquist said he’d recently lost his job before his death and his dependency on drugs had caused “conflict” with his father. Two months earlier, Lindquist had a stint in rehab, his sister, Danielle T. Nichols, told authorities.

Sergio Correa has a history of arson and robbery: In 2008, he was arrested twice for "first-degree attempted robbery with a deadly weapon, first-degree assault, first-degree larceny, second-degree arson and criminal use of a weapon," according to the Courant.

According to the affidavit, Ruth Correa once confessed the details of a robbery-turned-arson to a security guard, telling him she “has a thing of putting stuff in a guy’s drink, ‘roofies’ them, gets them high, then takes their money and whatever she can get of value.”