One of the forms of using passive verbs is: Object + Verb + "By + Subject" ("optional").


  • Sarah was killed by a police officer.
  • My cat was killed by neighbor's dog.
  • The book was given to me by Rion.

I know one of the reasons why we use "passives" is because we don't care why something happened. We just want to pay attention to the fact that an action occurred to us. When we say, "Sarah was killed", that means it's important to us she has died (someone killed her), not who killed her or why. But when we say, "Sarah was killed by a police officer", in my opinion it can be a mistake.

We can say, "Sarah was killed. The murderer was a police officer."

I think using "By + Subject" is wrong. If you want to use a subject, don't use a passive verb. Or if you want to use it, don't use a subject.

Am I right or not? Why?

  • 2
    If we say Sarah was killed, it's highly unlikely we don't think it's important who killed her or why. Quite possibly we don't know who killed her, but the most likely reason for saying was killed rather than is dead or just died is because someone murdered her (she didn't die accidentally, or of natural causes). Whatever - you're completely mistaken if you think Sarah was killed by a police officer is somehow less "natural" phrasing than Sarah was killed by a knife-wielding terrorist. Aug 8, 2023 at 17:15
  • I meant those reasons (who killed her or why) are in second . The most important thing is she is not hear anymore.
    – user175480
    Aug 8, 2023 at 17:17
  • You might say My cat was killed by a neighbour's dog (note the spelling!) to someone who knew the cat, or as part of a conversation about cats. If the conversation was about vicious dogs, you might say A neighbour's dog killed my cat instead. Aug 8, 2023 at 17:58
  • by X is not by + subject. The X is called the agent. It is never a mistake to cite the agent in a passive sentence, all other things being equal.
    – Lambie
    Jan 30 at 18:02

2 Answers 2


Both passive voice and active voice are both grammatically correct. In informal speech and writing, passive voice is very common. Different formal contexts might have different preferences for active or passive voice but there isn't one right way/wrong way.

Saying Sarah was killed by a police officer is grammatically correct and similar to sentences that native speakers say frequently. In academic writing, it would probably be better to say "A police officer killed Sarah." But outside of formal contexts, it doesn't really matter.

In short, you are welcome to have your own opinion. But your claim isn't broadly seen as correct or as incorrect. Most native speakers don't really think about passive or active voice much at all.


It is perfectly natural to say "Sarah was killed by a police officer" and it does not undermine the purpose of passive voice. Word order is very important to the meaning of English sentences, so simply by placing "Sarah was killed" at the beginning you are emphasizing it. In fact, separating the statement into two sentences places more emphasis on the identity of the killer, because the audience will infer that this information was too important to be confined to a subordinate clause.

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