Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: Witnessing the murder of his colleague Owen, Jack shoots his killer in the forehead, killing him in an act of swift revenge.

Jack saw his partner killed, so he shot the killer in the forehead out of revenge.