There can be lots ideas going on in a killers head and so can yours like wondering why they want to kill innocent people.I think that they do have reasons sometimes but occasionally it just comes with no explaining behind it although things shouldn`t have to end with killing in any circumstance! Here I`m going to explain why people will go this far to kill.
With certainty, I think people kill because of poverty. They feel that`s the only way to earn money to provide for their family which is not doing very well financially and they can`t have the qualification as they don`t have money to pay for university. The facts show that they have nothing on their status that leads to them probably not getting a proper job that pays for life essentials-not even extra stuff.On channel 5 they have a programme where people tell there story also linked with helping their family.https://www.channel5.com/show/gangland/
Another way people want to kill people is because of hate and someone owes them something.For example, if someone has an abiding hatered for someone they feel and end up killing them.If someone owes someone money they get really angry and aggressive that they kill them in a flash and regret it all through their life some don't because they do not turn over a new leaf!