MILWAUKEE, Wis. (WTAQ) - The federal courthouse in downtown Milwaukee was evacuated Tuesday because of a suspicious package that turned out to have school supplies.

The package was found in a charity donation bin about 3:30 p.m. A bomb-sniffing dog reacted to the package, and that caused authorities to empty the courthouse.

Streets were closed up to 5 blocks away – and that caused traffic tie-ups downtown, just as Milwaukee’s rush hour was getting started.

The package was tightly wrapped with tape, and the Milwaukee County bomb squad dismantled it – only to find the school supplies inside.

Police Chief Ed Flynn said officers did not overreact. He said they had to assume the package was threatening, based on the police dog’s reaction.