Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
As soon as the manslayer presented himself at the city of refuge, the elders of the city were to hold an inquiry, and receive him provisionally into the city. Afterward, when the avenger of blood should have tracked his victim to the city, and appear to claim him, a more formal and thorough investigation Jos 20:6 was to be made. Consult the marginal references.