The teen was detained after being questioned all day by investigators headed by Milan juvenile prosecutor Sabrina Taranto.
Judicial sources said there is no clear motive behind the triple murder.
“It will be necessary to wait a long time before explaining such an atrocious act,” they noted.
The 17-year-old on Sunday confessed to allegedly killing his parents and 12-year-old sibling.
He changed his previous version of events, according to which he had killed his father after the man had stabbed his mother and brother to death.
The teen said he was woken by his mother and brother’s screams and had walked into his sibling’s room to find his dad holding a knife beside their bodies.
During questioning with investigators, the teen said he felt a “disquiet”, a “sense of “oppression” and estrangement from his family and society in general, investigative sources said.
The teen appeared “very frail” and cried at length, they said.
The 17-year-old is now being held at Milan’s Beccaria juvenile detention facility ahead of a hearing to confirm his arrest.
ANSA
