Looking for the "why"

A day or two ago, in a radio segment about the demonstrations at the funeral home holding the body of the older Boston marathon bomber, the protestors not wanting his body buried here, the interviewer pointed out that this had not happened for other mass murderers. The excuse given was that this bombing was ideological, not the result of mental illness, as if a mentally ill person can't develop an ideology influenced by their disordered thinking. This is an example of the widespread habit of simplistic thinking. The question should be why he developed this way of thinking.

Actually, from the meager amount we know of him and his family from news media, there is reason to suspect the older bomber could have been mentally ill. (It appears the younger brother might have been a victim of influence by his older brother.)

A Facebook friend pointed out that he could have sustained brain damage from his boxing, and hopes he would have an autopsy that would look into this. The very purpose of boxing is to inflict enough brain damage on your opponent to temporarily disable him. Charles Whitman, the Texas bell tower sniper, left behind writings about being obsessed with killing his family, and not understanding where these feelings came from. He wanted his brain examined after his death. He sought help, but didn't get it. After his death, it was discovered he had a tumor in a part of his brain involved with emotions. It is not unusual for brain damage to affect a person's personality and emotions, and thus their actions and ethics.

He might have had schizophrenia. This is caused by faulty brain chemistry, usually caused by one's genes. It usually become apparent in young adulthood. A person with it often has close relatives with unusual ways of thinking. Stress can activate it in a person who is susceptible. It is likely that other genes, and brain damage from other reasons, would activate it in a person who is susceptible. His mother certainly sounds like someone who might be carrying a gene that causes it.