adjectives - How to differentiate agents that cause harm but may or may not have the intent of doing so?

If I harm someone/something without having the intent to do so, am I being aggressive, hostile, or something else? What if I had the intent?

I'm looking for ways to describe and differentiate agents which cause harm without intent (sometimes without even consciousness, e.g. a disease) from agents that cause harm with intent (e.g. me, hitting someone because I'm angry at them).

Any help would be appreciated, thanks.

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Background information:

I'm writing an article about the risks of a possible emergence of artificial intelligences with human-level intelligence or beyond. One important part of it is explaining to the author that an AI could cause harm to humans without any intent to do so (much like I do when I accidentally step on ants during a walk in the park). Alternatively, it could also decide to harm humans and then act accordingly. I consider both cases fundamentally different, and I refer to them throughout the case, so it would be convenient to have an adjective that summarizes those alignments.

Answer

Malevolent and negligent come to mind

malevolent
1: having, showing, or arising from intense often vicious
ill will, spite, or hatred

"Malevolent." Merriam-Webster.com. Merriam-Webster, n.d. Web. 19 Apr. 2016.

negligent
1 a : marked by or given to neglect especially habitually or culpably
1 b : failing to exercise the care expected of a reasonably prudent person in like

circumstances

"Negligent." Merriam-Webster.com. Merriam-Webster, n.d. Web. 19 Apr. 2016.