Slaveholders could seize an alleged runaway in free territory and bring the accused before a federal judge or local magistrate to prove title to the slave and obtain a certificate of rendition entitling the master to remove the slave from the free jurisdiction. The law placed most of the burden of slave catching on masters, including the burden of dealing with uncooperative Northerners, and it made rendition hearings inconvenient to arrange because few federal judges were available to participate. The 1850 Fugitive Slave Act provided for federal circuit courts to designate commissioners specifically to hear rendition proceedings, and it authorized commissioners and federal marshals to form a posse of bystanders to capture runaways.
