The alleged murder took place in the city of Bolzano in the northern Italian province of South Tyrol when teachers Peter Neumair and Laura Perselli went missing earlier this year.
Laura’s dead body was later found in Adige river with signs of strangulation while her husband’s body never surfaced, although traces of his blood were found on a nearby bridge.
The victims’ son, the bodybuilder Benno Neumair, 30, was taken into custody on January 29.
He has now confessed to the killing saying that he killed his father after a brief fight and then murdered his mother without a word of explanation when she walked in on them.
The argument that led to the murder started when the father asked his son to get out of bed and take the family dog out for a walk.
When he refused an argument developed. Benno said: "Dad accused me of being a failure. I just wanted silence. So I shut him up."
He said he had gone to his room to escape being scolded by his dad.
He objected to the fact that his father had followed him inside the room when he had gone to bed and fallen asleep after playing on his computer.
He complained that his dad had woken up and continued to complain that he was not doing his share of the household chores.
He decided to strangle him to stop nagging.
He said: "I took the first climbing rope I found from the plastic tray of my tools. We were in the hallway and we fell together on the ground. I just remember that I squeezed very tightly.”
Benno said that his mum returned home soon after and he strangled her with the same rope.
He said: “I did it without even saying goodbye.”
The son said that he then threw their bodies off a bridge into the river.
The young man is now in prison in Bolzano on charges of murder and body concealment as the investigation continues.
