MADISON, Wis. (CBS 58) -- Another lawmaker says they've received suspicious mail, this time in downtown Madison. 

A spokesperson confirms Congressman Mark Pocan received a piece of mail Monday, Oct. 19, similar to suspicious envelopes sent to lawmakers and officials nationwide. 

Pocan's office said the fire department was notified and a hazmat team responded to the downtown Madison office Monday. Initial on-site testing came back negative for several factors. The spokesperson says the envelope and contents were taken to the State Lab of Hygiene for further testing. 

The FBI and US Postal Service confirmed they are investigating similar cases. 

Last week, Congresswoman Gwen Moore said her office received a suspicious letter. 

Authorities have not identified the substance or the person responsible.