Learn German: Die Polizei hat den Täter geschnappt. - The police caught the perpetrator.

Unlike in English, where "police" is often treated as a plural noun, the German word die Polizei is strictly singular and feminine. Therefore, it takes the third-person singular verb hat. If you need to talk about multiple police officers, you would use the plural noun die Polizisten.

Is schnappen the standard legal term for arresting someone?

No, schnappen is a more informal, colloquial verb that means "to nab," "to catch," or "to grab." While it is very common in everyday speech, thrillers, or casual news, a formal police statement or serious news report would use more official vocabulary like festnehmen (to apprehend/detain) or verhaften (to arrest).

What word family does Täter belong to?

Der Täter comes from the noun die Tat, which means "the deed" or "the act." Although a Täter is literally just a "doer," in modern German it is almost exclusively used in criminal contexts to mean "perpetrator" or "culprit" (someone who has committed a Straftat, or crime).