Learn Russian: Это ограбление совершил сообщник! - This robbery was committed by an accomplice!

In English, we often use the passive voice to put the most important new information (the focus) at the end of the sentence. Russian achieves this same focus simply by changing the word order. It puts the known topic, Это ограбление, at the beginning and the new, surprising information, сообщник, at the very end, while keeping the active verb совершил. This Object-Verb-Subject structure is extremely common in Russian for shifting emphasis without needing a passive construction.

Both ограбление and сообщник look like they could be the subject. How can we tell who did what?

We can tell by looking at the verb's gender agreement. ограбление is a neuter noun, while сообщник is masculine. The past tense verb совершил has a masculine ending, meaning сообщник must be the subject in the nominative case. Therefore, Это ограбление is the direct object in the accusative case, which looks identical to the nominative for neuter inanimate nouns. If the robbery were the subject, the verb would be совершило.

Does putting сообщник at the end also affect whether it translates to an accomplice or the accomplice?

Yes! Because Russian does not use articles, word order does this job. Placing a noun at the end of the sentence signals that it is new information (the rheme), which naturally translates to the indefinite meaning: an accomplice. If you wanted to say that THE accomplice committed this robbery, you would put the known subject at the start: Сообщник совершил это ограбление!