ROSWELL, Ga. -- Authorities are looking into several calls of suspicious envelopes in a Roswell neighborhood where Republican 6th District candidate Karen Handel lives.

According to Roswell Police spokesperson Lisa Holland, police received a call around 1:30 p.m. that a person had gotten an envelope in a mailbox that contained an unidentified powdery substance in the County Club of Roswell.

Police confirmed that they are now investigating a total of five calls of other homes that have also received powdery substances. At this time, they don't know if there are any more out there that have been delivered. The U.S. Postal truck that was involved has been notified.

Right now authorities, including the FBI and Roswell Police, are searching several streets including Roxburg Drive, Holcomb Bridge Road, Old Alabama Drive and Bankside Drive.

The FBI confirmed that they are also investigating the situation.

Handel, who is running for the Georgia 6th District Congressional seat, confirmed that she also got an envelope at her home and released a statement on the situation saying, "This afternoon we had some suspicious packages delivered to our house and to our neighbors. The packages contained threatening letters and a suspicious substance. The police were quickly notified and street is now being blocked off. We will continue to coordinate with law enforcement as necessary.”

Shortly after police responded to the Roswell neighborhood, the FBI confirmed they were looking into another possibly related threat of a powdery substance received at the Atlanta Fox News affiliate and later at 11Alive News. However, officials later confirmed that the both cases involved baking soda.

The campaign office for Jon Ossoff, running against Handel in the June 20 election, said they were forced to increase security measures after escalating threats of violence earlier this week.

PHOTOS: Suspicious envelopes found in Karen Handel's neighborhood