A welfare check at a family home in Acton, Massachusetts, on 11 August took a disturbing turn.
Police found two family members dead inside the house, while 17-year-old Arjun Aravind was nowhere to be found.
Hours later, investigators located him nearby.
As police began piecing together what happened, they uncovered details about Arjun's online activity that added another layer to the case.
What happened that day, and what led investigators to the teenager?
How Did The Case Begin?
The investigation began after Arjun's father could not reach his family.
A tutor had also arrived at the family's Martha Lane home for a scheduled appointment, but no one answered.
At about 6:37 pm on 11 August, Arjun's father contacted Acton Police for a welfare check. He had last spoken to Sudha that morning before leaving for work.
Siddharth had been seen at a recreation centre earlier that day and returned home around noon.
Police found Siddharth dead on the first floor and Sudha dead in the finished basement.
Both had suffered "obvious trauma", according to the district attorney. The exact cause and manner of death, and the weapon used, had not yet been determined.
Arjun, 17, was not at home. The Times of India identified him as an Indian-origin teenager.
Acton Police Chief Douglas Sturniolo said police knew Arjun because he had run away from home at one point the previous year.
Investigators believed Arjun had left in his mother's Honda Accord.
Where Was Arjun Found?
Police searched for Arjun after discovering that he was missing from the home.
The Honda Accord was later found in a parking lot in Wayland early on 12 August, after local police responded to an unrelated business alarm.
Arjun was inside the vehicle.
Police took him into custody without incident.
What Charges Does He Face?
Arjun has been charged with two counts of murder in connection with the deaths of his mother and brother.
He also faces two counts each of assault and battery on a household or family member and assault and battery. Prosecutors have also charged him in connection with using a vehicle without authority and stealing a motor vehicle.
Because Arjun is 17, the court process involves different jurisdictions.
He was arraigned on some of the vehicle-related charges in Lowell Juvenile Court. However, that court does not have jurisdiction over murder charges.
The murder and related assault charges are being handled in Concord District Court.
What Did Investigators Find On ChatGPT?
This is the part of the case that has attracted particular attention.
Middlesex District Attorney Marian Ryan said Arjun had recently displayed what investigators considered concerning behaviour.
She said investigators found that he had used the internet and ChatGPT to search for theoretical ideas or fantasy stories involving the killing of his family.
Other reports have described the material as fictional or Gothic-style stories.
However, the evidence currently available does not establish that ChatGPT caused the alleged killings.
It also does not establish that the searches were the motive.
The online activity is being examined as part of the wider investigation into Arjun's behaviour before the deaths.
Why Did Arjun Allegedly Kill His Family?
Police have not publicly established a motive.
Investigators have not said what led to the alleged attacks or what happened inside the house during the period in which Sudha and Siddharth were last known to be alive.
The ChatGPT and internet activity may form part of the evidence being examined, but it cannot by itself establish why the killings allegedly took place.
The medical examiner's findings and the continuing police investigation could provide more information about the deaths and the sequence of events.
TL;DR | News At Glance
Who is Arjun Aravind?
A 17-year-old Indian-origin teenager from Acton, Massachusetts, who has been charged with two counts of murder.
Who were the victims?
His mother, Sudha Venkatesan, 45, and his younger brother, Siddharth Aravind, 14.
How were they found?
Police conducted a welfare check after Arjun's father could not reach his family.
Where was Arjun found?
Inside his mother's Honda Accord in a Wayland parking lot on 12 August.
What did investigators find?
Authorities said he had used the internet and ChatGPT to explore theoretical ideas or fantasy stories involving the killing of his family.
Did ChatGPT cause the killings?
Authorities have not established that.
Is the motive known?
No. Police have not publicly established a motive.
What happens next?
Arjun faces murder proceedings while the investigation into the deaths continues.
