The Greek noun phoneus means a murderer, a person culpable for unlawful killing. Acts uses it for Barabbas, for Stephen's accusation against those who killed the prophets and betrayed Jesus, and for an islanders' hasty conclusion about Paul after a snakebite. First Peter distinguishes suffering for allegiance to Christ from punishment for murder and other wrongdoing.
Jesus' parable can call violent characters murderers, and Revelation includes murderers among those facing final exclusion and judgment. The term is morally severe, so it must not be attached to a person merely because a rumor, political slogan, intrusive thought, accident, military association, or unexplained event has produced suspicion. Acts 28 deliberately shows an accusation formed from inadequate evidence and then reversed.
Acts 7 records a specific prophetic confrontation within Israel's story; it must not become an accusation against Jewish people as an ethnic or religious group. A congregation should name proven violence truthfully, protect people at risk, cooperate with lawful investigation, and hold repentance together with justice. Forgiveness does not require survivors to deny facts, surrender safety, or obstruct accountability.