Titus Livius (Livy), The History of Rome, Book 25
Frank Gardener Moore, Professor Emeritus in Columbia University, Ed.

17. There are some who maintain that in the region of Beneventum, by the river Calor, he had gone out of the camp with his lictors and three slaves to bathe, while enemies, as it [2??] happened, were hiding among the willows growing on the banks, and was slain, naked and unarmed and defending himself with stones which the river rolls along. [3] There are some writers who say that on the advice of the soothsayers he had gone five hundred paces from the camp to make atonement on an uncontaminated spot for the prodigies mentioned above, and was overpowered by two troops of Numidians who chanced to be in ambush there. So far are both the place and the manner of his death from being established, in spite of his eminence and distinction. [4] In regard to Gracchus's funeral also reports vary. Some relate that he was buried in the Roman camp by his own men, others —and this is the prevalent report —that [5] by Hannibal's order a pyre was erected directly outside the gate of the Carthaginian camp, and that the army defiled under arms, with dances by the Spanish troops and such movements of weapons and bodies as were customary for each tribe, while Hannibal himself [p. 411]honoured the obsequies with every tribute in act¹ and word. [6] These are the statements of those who vouch for its occurrence in Lucania. If you incline to believe those who state that he was slain at the river Calor, the enemy gained possession of Gracchus' head only. [7] This being brought to Hannibal, Carthalo was at once sent by him to bring it to the Roman camp and Gnaeus Cornelius the quaestor. He conducted the funeral of the general in the camp, while the people of Beneventum joined with the army in doing him honour.