Yep. I don't think everyone has homicidal thoughts, certainly most would never seriously consider murder, but there is a certain situation/are certain situations for every person that would cause them to commit murder. Maybe a 'kill this stranger o your daughter dies' scenario o something. And, of course, we all have the physical means to commit murder. We have our own two hands, o we could get someone else to do the dirty work for us. *shrugs* Whatever the situation, yes, we are all capable of murder.
Everyone has inhibitions inside them that would make them feel like they would have the ability to commit murder, but I think not every person can actually perform the deed. Most people assume that dado the "perfect" situation, such a thing would drive someone to commit an act, but not everyone has the willpower inside them. There's that block in possibly few chosen people that would stop them before they killed someone, whether it be moral conscience o just fear of taking the life of another.