In act 4 of Julius Caesar, who dies and how do they die?

Act IV begins with Antony and Octavian, along with Lepidus, listing the names of those conspirators and alleged conspirators who might be problematic for them in the future. They say that Publius and Lepidus's brother must die. But we do not learn of their murder in this act. The one character who dies in this Act (albeit offstage) is Portia, Brutus's wife. Brutus announces her death to Cassius after their dispute in Act IV Scene 3. She has died, according to Brutus, by "swallowing fire," a horrific means of committing suicide. Brutus says, in effect, that she has killed herself because she was "impatient of my absence" and fearing the worst as Antony and Octavian appeared to be gaining in power in Rome. She may have believed that she would be killed as the wife of the chief conspirator against Caesar, and wished to avoid such an ignominious end.