Two brothers in Dallas, Texas have killed their entire family after they made a pact to kill their relatives and then themselves.

One of the brothers detailed the said plan in a six-page suicide note that was posted online. In the letter, he detailed his years-long battle with depression and self-harm.

The 19-year-old boy also expressed his hatred at the latter seasons of the TV sitcom "The Office," and ranted about inadequate gun control in the United States, according to a Daily Mail report.

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The Horrific Incident in Texas

Officers responded on Monday after receiving a call at around 1 a.m. asking for a welfare check to a home in the 1500 block of Pine Bluff Drive. Police said the call came from a friend who was concerned that a person inside the residence was suicidal.

When police arrived at the scene, they discovered six bodies, all with gunshot wounds, inside the family's home, The Sun reported.

"Apparently two brothers made an agreement to commit suicide and ended up taking the entire family with them," police Sgt. Jon Felty told the Dallas Morning News.

Police confirmed that 19-year-old Farhan Towhid and 21-year-old Tanvir Towhid carried out the massacre that killed their parents, sister, and grandmother.

Authorities believed that Farhan had convinced and teamed up with his older brother to kill the rest of their family and then themselves.

"Hey everyone. I killed myself and my family... If I'm going to die, I might as well get some attention," Farhan Towhid reportedly wrote in the suicide note before he killed himself and his family.

The Daily Beast reported that Farhan Towhid also bragged about how easy it was for him and his brother Tarvin to buy guns.

The murder-suicide was very shocking to the tight-knit Bangladeshi American community that the family belonged to.

Sahnewaz Hossain told the Dallas Morning News that the mother always talked about the two brothers, saying that they were good in studies and getting to good schools with scholarships.

The victims were identified as Towhidul Islam, 54; his wife, Iren Islam, 56; Farbin Towhid, the twin sister of Farhan; and grandmother Altafun Nessa, 77.

Farhan Towhid wrote the suicide note in Google Docs and posted it on his Instagram account. He and his older brother were both former students at the University of Texas at Austin.

The note stated that he decided to kill his family as he believed that his loved ones would be miserable if they will live without him and they would spend the rest of their lives feeling guilt and despair.

Police said there was no record of any previous disturbances at the family's residence.

Depression in the U.S.

According to a Mental Health America National report, major depression affects 6.7 percent of American adults each year.

Only about 35.3 percent of those suffering from severe depression seek treatment from a mental health professional as many people still believe that depression is not a serious illness.

There can be many factors that can contribute to clinical depression, such as biological, cognitive, and gender. It was reported that more women experience depression than men. The reasons are still unclear, but it was believed that it may include hormonal changes that women go through.

Depression is also more likely to happen with illnesses, such as heart disease, cancer, Parkinson's disease, diabetes, Alzheimer's disease, and other hormonal disorders.

Depression can also be caused by the side effects of some medications. Certain situations, particularly difficult life events, can also trigger depression.

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