Man kills in-laws with flamethrower

In this bad world of ours, there have always been people doing things which normal people cannot understand. Why somebody would do mass murder, or torture other people, or commit incest, or many other such things. You must have also read jokes somewhere about the normally strained relationship between a husband and his in-laws, but would you ever imagine a man burning his aged and infirm inlaws to death ? Read on about this guy in Austria (the same country where a man confined his daughter for 18 years and had 7 forced children through rape with her):

A man in eastern Austria used a homemade flamethrower to kill his wife's elderly parents, police said Saturday. The incident happened at 10pm (4pm ET) Friday in Hartberg, a town in Austria's Styria region, about 22 miles (35.5 kilometers) from the Hungarian border, said Chief Anton Kiesl of the state police homicide division.
Kiesl said the man first spread gas in the room of his 84-year-old in-laws, then lit a homemade propane gas bottle and threw it at them, burning them alive. The mother-in-law suffered from diabetes and her legs had previously been amputated, so she was unable to flee and died in her bed, Kiesl said. The father-in-law was able to flee but died soon afterward; police found his body on a garden bench near the family's apartment, Kiesl said.

Police are investigating as to a motive, but there can be no motive that would justify the murder of elderly people, unable to prevent harm to themselves; and to do this against an elderly lady whose legs have been amputated and who is unable to run to safety must require a horrible mind.