The verb ἐπεμαρτύρατο is a deponent middle form of μαρτυρέω, here used with an accusative object (τινʼ) to mean 'he gave testimony against someone' or 'he swore to the guilt of someone.' While μαρτυρέω often appears with a genitive of the person accused in other contexts, the accusative construction here is standard for the specific forensic sense of 'bearing witness against' in Attic tragedy and comedy, though the middle voice emphasizes the personal involvement of the witness in the act of accusation. The phrase οὑχῖνος (a rare form of οὐχὶ ὅς, or possibly a textual corruption of οὐχὶ ὅσος) requires scrutiny: if read as οὐχὶ ὅς, it introduces a rhetorical question meaning 'Is he not the one who...?', but if it is a corruption of οὐχὶ ὅν (accusative), it would mean 'Is he not the one who...?', which fits the accusative object τινʼ. The most likely reading, supported by some manuscripts, is οὐχὶ ὅς, where the relative pronoun is attracted to the case of its antecedent implied in the context, or it is a crux where the relative pronoun refers to the subject of the main clause. The construction is syntactically complex and has been the subject of textual debate, with some editors proposing οὐχὶ ὅν or οὐχὶ ὅς depending on the intended meaning.