Accidentally killing monkey in a dream, what can it mean?

I had a strange dream today,

There was allot of familiar things, places and people I knew mixed with ones that I didn't.

The only part I remember clearly is near the end.

I was in a room in a building, looking out I saw a blond ape and a black monkey with a patch of white on it's throat. They where on the rooftop of a lower building near by.

They jumped over to the ledge of my building and seeing a window that was slightly open I closed it, but there was no way to lock it.

The ape sat there and didn't look interested, but The black monkey had come up to the window. I slammed the glass hard to scare him away, he was so startled by it that he jumped off the ledge. A moment later I herd him make this awful sound and I knew that he died.

I woke up after that feeling very sad.