Would it be more accurate to translate this as: " you may not ask him anything past what's in the report" or " you won't get anything new out of him other than what's already written in the reports. "
He tells them not to ask him or simply states it's useless to try? It's a line from a manga i bought but online the translation is different
The verb 聞き出す includes the meaning of getting information from someone. The sentence means "(Even if you try asking him,) you cannot get anything new out of him". In other words, asking him itself is possible but useless.