Two brothers, children of Bangladeshi expatriates, who killed four of their family members before killing themselves on Saturday, wrote in an Instagram post that they had been suffering from depression.

The murder-suicide also exposed how easy it is to obtain firearms in the USA. They said the gun control was “a joke”, reports the New York Post.

In a 12-page note initially linked to his Instagram page, Farhan Towhid, 19, said that he and his 21-year-old brother, Tanvir Towhid, thought that getting guns would be the most challenging part of the murder-suicide plot.

But they found “gun control in the US is a joke”, Farhan wrote in the note. He said all his brother had to do was go to a shop “say something about wanting a gun for home defense, sign some forms, and that was it”.

There was a question if he had any mental illnesses “but he lied”, Farhan wrote. “He literally just said no. They didn’t ask for proof or if he was taking any medication (he was).”

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Police say they believe the Bangladeshi brothers killed their parents, Iren and Towhidul Islam, grandmother Altafun Nessa, and Farhan’s 19-year-old twin sister, Farbin, on Saturday at the family’s home in Allen.

All six victims were discovered during a wellness check at about 1am on Monday, according to media reports. It was not immediately clear what guns were used.

‘Battling depression’

Farhan wrote that their “simple plan” was to get two guns take out the four members of their family before killing themselves.

The incident was a result of both brothers battling depression, he wrote.

“I’ve had depression since 9th grade (2016). Not the ‘damn, I failed my test’ depression everyone says they have, more like a ‘I only cut myself twice today, that’s better than usual,'” Farhan wrote and noted that his brother’s condition “was much worse.”

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He described his brother as being a “genius” but “too depressed and socially anxious” to do anything.

Tanvir first suggested the murder-suicide plan in February and it was based on “pure logic,” Farhan wrote.

“I love my family. I genuinely do. And that’s exactly why I decided to kill them,” he said.