I am studying law back here and Canada, and there is one massive element I came to realize, which really made me think. In the first episode of the Monsters mini-series, before killing their parents, they were apparently buying guns in San Diego. Then, they drove back to their home, listening to music, signing, and decided to go through with the killings. However, in the documentary, it appeared they were already in the house before shooting.

Lyle had this argument with his mom and dad, and he was apparently scared according to Erik. That was the moment they both really thought their parents could killed them both. They said they decided to purchase both guns the Friday prior to the shootings in order to defend themselves. It was the same gun store in San Diego. The night of the killings, Lyle told his mom that they were both leaving. His dad heard the argument, and told Erik to go upstairs to his room and wait for him. That was the moment Lyle thought they would kill them. He ran upstairs to his brothers, and said that "it was happening now". They loaded the guns, and goodnight... It is around 1h15 in the documentary by the way !

In terms of law, that is a massive difference because the right to self-defense could MAYBE apply to the second case. They both thought they were in danger; however, it is hard to know or prove if the danger was imminent. In the "Monsters" series, they were no imminent danger with the chronology... They went to the gun store, came back to the house and simply killed both parents.

Am I the only one that noticed this major difference ?