As Tribune of the People in 63 BC, Labienus prosecuted C. Rabirius, who was defended by Q. Hortensius Hortalus (92 F 34–35) and Cicero (Cic. Rab. perd.). Rabirius was accused of involvement in the killing of L. Appuleius
F 1 Cic. Rab. perd. 6–8, 10, 12–13, 18, 22, 28–29
nunc quoniam, T. Labiene, diligentiae meae temporis angustiis obstitisti meque ex comparato et constituto spatio defensionis in semihorae articulum coegisti, parebitur et, quod iniquissimum est, accusatoris condicioni et, quod miserrimum, inimici potestati. quamquam in hac praescriptione semihorae patroni mihi partis reliquisti, consulis ademisti, propterea quod ad defendendum prope modum satis erit hoc mihi temporis, ad conquerendum vero parum.  nisi forte de locis religiosis ac de lucis quos ab hoc violatos esse dixisti pluribus verbis tibi respondendum putas; quo in crimine nihil est umquam abs te dictum, nisi a C. Macro obiectum esse crimen id C. Rabirio. in quo ego demiror meminisse te quid obiecerit C. Rabirio Macer inimicus, oblitum esse quid aequi et iurati iudices iudicarint.  an de peculatu facto aut de tabulario incenso longa oratio est expromenda?1 ... an de sororis filio diligentius respondendum est? quem ab hoc necatum esse
Saturninus (64A) in 100 BC under the ancient charge of perduellio; the proceedings took place before the People. In his speech Cicero comments on the arguments allegedly put forward by Labienus (TLRR 220, 221).
F 1 Cicero, Pro Rabirio Perduellionis Reo
Now, T. Labienus, since you have impeded my thoroughness by limit of time and have reduced the standard and customary period for the defense to the narrow limits of half an hour, one must submit both to the terms of the prosecutor, which is extremely unjust, and the power of the enemy, which is extremely wretched. Still, by this limiting regulation of half an hour, you have left me the part of an advocate, but have robbed me of that of a consul [in 63 BC], for the reason that this time will be almost sufficient for me for defense, but for protest too little.  Or perhaps you believe that I should reply at some length to you concerning the holy places and groves that you have said had been violated by this man here [Rabirius]; regarding this charge nothing has ever been said by you, except that this charge was brought against C. Rabirius by C. Macer [C. Licinius Macer (110), F 4]. With respect to this, I am amazed that you remembered what Macer, his enemy, charged C. Rabirius with, but forgot what impartial judges decided upon oath.  Or should a long speech be produced upon the charge of embezzlement or of the burning of public records [of which a relative of Rabirius had been acquitted and which does not apply to Rabirius]? ... Or should one reply rather carefully about his sister’s