A letter, which was addressed to Jersey City Mayor Steven Fulop, family and friends, was mailed to City Hall along with white powder and a picture of former New York Jets quarterback Tim Tebow.
According to Public Safety Director James Shea, an aide opened the letter and called the police immediately when the powder fell out of the envelope.
The building was evacuated as a hazmat unit, bomb squad and other emergency personnel determined the threat level.
The powder was determined not to be harmful to anyone, but there was more in the letter. Shea wouldn't comment on what the letter said because of the matter was still being investigated, but an anonymous letter source divulged further: "spiritual stuff: Heaven stuff. A picture of Tim Tebow."