Why did the guy who robbed me try to kill me even though I cooperated with him?

I was robbed at knifepoint in the parking garage after leaving work in February. I voluntary and without any resistance whatsoever handed over my wallet and iPhone. After I handed them over he stabbed me 9 times in the chest and abdomen. He had a ski mask on so it wasn't like I saw his face either. Luckily, The blade was only 3 inches long and didn't hit any vital organs. I could've bled to death but was found by someone a couple minutes later. I just can't make sense out of why this man so selfishly and heartlessly attempted to take me away from my family forever when he had absolutely no reason to do so. And what is even more frightening is that he is still at large.

He must not have liked the cut of your jib.

He's a bully likes to fed off of the weak

Some people are just evil. Some people are mentally ill. Some people are so under the influence of drugs they have no idea what's going on. Some are all three and lots more.

I'll bet he was black too, wasn't he?

Because he couldn't be sure that you didn't have a gun and weren't going to shoot him. In countries where law-abiding citizens are unarmed, the criminals don't try to physically harm their victims, because they don't need to. But in the US, they need to disable or kill their victims, to keep their victims from killing them.

He was probably high on some type of drugs.

Opportunistic criminals like this aren't always the most organized. It's not like this person put together a sophisticated plan to burgle your house. He was just looking for fast hit, probably to fund a drug habit. He apparently lost control of himself. I'm very sorry and hope you're able to recover fully.

Because he didn't want to worry about getting caught. You were a "loose end." Does it really matter? You survived the attack.

Wanna be cop. Any thing for a power feel.