The Federal Communications Commission is looking into Google "Street View" maps service to see if the company violated federal laws.
Google said last month that it was "mortified" to learn its Street View cars mistakenly collected e-mail addresses, passwords and other personal information.
"In light of their public disclosure, we can now confirm that the Enforcement Bureau is looking into whether these actions violate the Communications Act," said Michele Ellison, chief of the FCC's enforcement bureau, on Wednesday.
The revelation of the FCC probe comes after the Federal Trade Commission ended its investigation of Google's Street View service. The company pledged to improve its privacy and security practices.
A Google spokesman said in a statement on Wednesday that the company is sorry for mistakenly collecting payload data from unencrypted networks and is cooperating with regulators.
"We want to delete the data as soon as possible and will continue to work with the authorities to determine the best way forward, as well as to answer their further questions and concerns," the spokesman said.