A suburban Boston teenager murdered his mother and brother after using artificial intelligence “for theoretical ideas or fantasies regarding killing his family,” authorities said Wednesday.

Arjun Aravind, 17, of the affluent bedroom community of Acton, was charged with two counts of murder in the slayings of Sudha Venkatesan, 45, and Siddharth Aravind, 14, according to a statement from Middlesex County prosecutors.

The suspect’s tutor, who had an appointment at the family home on Tuesday, “was unable to make contact with residents upon arrival,” prosecutors said.

That’s when the suspect’s father — who last spoken to his wife when he left for work in the morning — called police, and officers “located the two victims dead inside,” with the suspect’s brother on the first floor and mother in the basement.

“The subsequent investigation indicates that Arjun had recently been demonstrating concerning behavior, including using the internet and ChatGPT to make searches including for theoretical ideas or fantasies regarding killing his family,” the district attorney’s office said a DA statement.

“It is alleged that Arjun fatally assaulted his mother and brother inside their home yesterday before fleeing the scene.”

The suspect and his mother’s car, a 2014 green Honda Accord, were missing from the home when the bodies were found, officials said.

An alarm was tripped at a parking lot in nearby Wayland early Wednesday morning, and that’s where law enforcement “located the suspect vehicle with Arjun inside. ” He “was taken into custody by police without incident,” prosecutors said.

It was not immediately clear on Thursday wheter Arjun Aravind had hired or been assigned a criminal defense lawyer to speak on his behalf.