被告人が審理中に保安係りのピストルを掴み判事を撃った。

。

The defendant grabbed a security guard's pistol during the trial and shot the judge.

Literal

Defendant [subject-が] trial-during [in-に] security-guard [possessive-の] pistol [object-を] grabbing judge [object-を] shot.

被告人 (ひこくにん, 'defendant') is the legal term. 審理中 ('during the trial') uses ~中 for 'during.' 保安係り ('security guard') is slightly old-fashioned phrasing. The sentence chains two actions with て-form: 掴み (grabbing) → 撃った (shot). Dramatic courtroom content with precise legal and firearm vocabulary.