"Financial stress does not appear to have been a contributing factor, as the suspect, Devan Kalathataka Raghavan Devarajan Kalathat was securely employed as an engineer," the police said.
"Both the guns used were .45 caliber semi-automatic pistols. They were legally purchased by Devarajan. One was purchased a month ago and the second a week ago," the police added.
The police also revealed the official names of the six people who died in the shooting on Sunday night. They termed Devan Kalathat aka Raghavan Devarajan, 42-as the suspect.
Other victims are Akhil Dev, 11, Negha Dev, 4, both children of Kalathat; Ashok Appu Poothemkandi, 35, Devarajan's wife's brother; Suchitra Sivaraman, 25, wife of Ashok Appu; and Ahana Ashok, 11-month daughter of Ashok Appu and Suchitra Sivaraman.
Police did not reveal the name of Kalthat's wife, who is critically wounded. But relations revealed her name as Aabha.
The murder suicide occurred on Sunday about 8:30 pm in the rented home on Headen Way in Santa Clara. The family moved in the rented home only a few days ago from Sunnyvale, police sources had informed.
Relatives in India revealed that a quarrel between Devarajan and Ashok Appu could be the reason for the murder.
Devarajan's family stays in the Wayanad district of Kerala, while his wife's family is in Ayyankolli, a border village in Tamil Nadu, not very far from Devarajan's house. He was a US citizen, who arrived in the US 15 years ago.
His children attended Challenger school in Sunnyvale.
Relations said Ashok Appu worked for Hewlett Packard in Bengaluru. He came to the US with wife and children a few weeks ago on an assignment for the company.
"The Consulate was informed by the Santa Clara Police on Monday afternoon seeking our assistance in contacting the next of kin of the deceased in India. We were able to inform the concerned family members in India about the tragedy," Ashok Kumar Sinha, Consul at the Indian Consulate in San Francisco said.
"Arrangements are now being made to transfer the remains to the family in India," he added.