The battle revealed the Army of Northern Virginia had another agenda. As the Confederate army swept northward into Pennsylvania, the soldiers rounded up escaped slaves and free blacks. African-Americans, men, women and children were gathered up and taken with the army as they marched north. When the Army of Northern Virginia retreated, they took the captured black people, estimated to be over a thousand, back to Virginia. There those who had escaped slavery were returned to their slaveowners. Others were sold at auction or imprisoned. Lee may not have ordered the "slave hunt". Once in Pennsylvania he told his troops "no greater disgrace could befall the army," or discredit the Confederate cause, "than the perpetuation of the barbarous outrages upon the unarmed and defenceless [sic] and the wanton destruction of private property that have marked the course of the enemy in our own country." This did not stop his officers and men from rounding up blacks. In one case at Mercersburg, Pennsylvania, soldiers threatened to burn "every house which harbored a fugitive slave". They gave the people in their homes 20 minutes to give up any black people.