Learn Farsi: قاتل فرار کرد، اما پلیس گرفتش. - The murderer escaped, but the police caught him.

The word گرفتش combines the verb گرفت (caught) and the pronominal enclitic ـَش (him/her/it). When you use these attached pronouns as a direct object on a verb, you do not use the object marker را (ra).

Is the attached pronoun in گرفتش pronounced as "-ash" or "-esh"?

In formal written Farsi, the third-person singular suffix is ـَش (-ash). However, in spoken and everyday Farsi, the vowel softens and it is pronounced as ـِش (-esh). You will almost always hear this spoken as "gereftesh".

In English we often treat "police" as a plural noun, but is the verb singular or plural in this Farsi sentence?

The verb گرفت is third-person singular. In Farsi, the word پلیس (police) acts as a standard singular collective noun. If you specifically wanted to talk about plural officers, you would say something like ماموران پلیس (police officers).

Since the enclitic attaches to the very end of the simple verb گرفت, what would happen if we used a compound verb instead?

If you used a compound verb like دستگیر کرد (arrested), the enclitic pronoun would attach to the noun part rather than the verb part. For example, "arrested him" would be دستگیرش کرد (dastgir-esh kard), not "dastgir kard-esh".