Plato, Laws 874a

καθιζέτω τῶν γειτόνων τὸν ἐγγύτατα ὁ προσήκων γένει, ἀφοσιούμενος ὑπὲρ αὑτοῦ τε καὶ ὑπὲρ τῆς συγγενείας ὅλης, τὸ δὲ ὀφλὸν ἐξορίζειν, καθάπερ ἐρρήθη τὸ τῶν ζῴων γένος.ἐὰν δὲ τεθνεὼς μὲν αὖ τις φανῇ, ἄδηλος δὲ ὁ κτείνας ᾖ καὶ μὴ ἀμελῶς ζητοῦσιν ἀνεύρετος γίγνηται, τὰς μὲν προρρήσεις τὰς αὐτὰς γίγνεσθαι καθάπερ τοῖς ἄλλοις, προαγορεύειν δὲ τὸν φόνον τῷ δράσαντι, καὶ ἐπιδικασάμενον ἐν

to pass judgment on it, thus making atonement on behalf of himself and all his kindred, and the thing convicted they shall cast beyond the borders, as was stated in respect of animals. If anyone be found evidently dead, and if his slayer be unknown and undiscoverable after careful search, then the warnings shall be the same as in the other cases, including the warning of death