An Indian-origin family, including their 4-year-old twin boys, has been found dead at their home in California with the police investigating the case as a murder-suicide, the second such incident in less than two months that has shocked the community in the US.

The victims, hailing from Kerala, have been identified by the friends as Anand Sujith Henry, his wife Alice Priyanka, and their 4-year-old twin boys, NBC Bay Area reported.

However, the victims' identities have not yet been released, police said.

The incident took place in San Mateo on Monday, police were quoted as saying by the the report.

On Monday, Police said a 911 call spurred a welfare check at the location after someone reported they hadn't heard from the residents for some time. They arrived and checked the exits of the home and found no signs of forced entry.

"Unfortunately, we located four deceased people inside the home. One adult male. One adult female and two children," said Jerami Surratt, public information officer with the San Mateo Police Department.

The case is being investigated as a murder-suicide, police said on Tuesday.

According to court records, the husband filed for divorce in December 2016 but apparently did not go through with it.

The two young children were found inside a bedroom, police said.

"The children did not have any gunshot wounds. Unfortunately, they were found deceased, so that will be part of the autopsy, to figure out the cause of (the children's) death," Surratt said at a Tuesday afternoon press conference.

Sources with direct knowledge of the investigation said police believe the boys were smothered, strangled, or given a lethal overdose because there was no sign of trauma on their bodies.

The man and woman were found inside a bathroom, according to police. They both had gunshot wounds.

A 9-millimeter pistol and a loaded magazine were found in the bathroom, police said.

The deaths appear to be an isolated incident, and there is no danger to the public, police said.

"We are confident the person responsible was located within the home," police said in a statement.

"This is not a normal call for anyone. It's tragic for the family, the community, the officers..," said Surratt.

At the State of the City address on Monday night, San Mateo Mayor Lisa Diaz Nash held a moment of silence for the four people found dead in the home.

"It was horrific, it was devastating to all of us, to the community as well as to our San Mateo Police officers." Neighbors were shaken up by the tragedy.

Matthew Sheldon and his daughter, Marianne, have both lived in San Mateo their entire lives and they say they've never seen anything like this.

"There's hardly any deaths in this area ever," Matthew said.

Other neighbors noted that San Mateo, despite how relatively safe and quiet, isn't immune to death or tragedy.

This incident is similar to the December 28 case where a wealthy Indian-origin couple and their teenage daughter were found dead in their USD 5 million mansion in Massachusetts.

Rakesh Kamal, 57, his wife, Teena, 54, and their 18-year-old daughter, Ariana, were found dead in their 11-bedroom and 13-bathroom mansion last month.

There have been seven deaths of an Indian or Indian-American in the country in recent months.

On February 10, a 41-year-old Indian-origin IT executive died after suffering life-threatening injuries during an assault outside a restaurant in Washington.

Before that, Syed Mazahir Ali, an Indian student was attacked by robbers in Chicago.

Earlier, 25-year-old Indian student Vivek Saini was fatally attacked in Georgia state’s Lithonia city by a homeless drug addict.

Another student identified as 19-year-old Shreyas Reddy Beniger was found dead in Ohio. However, local authorities have ruled out foul play.

Sameer Kamath, a 23-year-old Indian-American student at Purdue University, was found dead in a nature preserve in Indiana on February 5.

Another Indian student, identified as Neel Acharya at Purdue University, Indiana, was confirmed dead days after being reported missing on January 28.

Akul B Dhawan, an 18-year-old at the University of Illinois Urbana-Champaign, was found dead last month with signs of hypothermia.

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