The controversy stems from the search engine's Street View feature, which provides pictures of neighborhoods.
Authorities say the feature might violate privacy laws.
Last month, Google representatives acknowledged they had mistakenly collected data over public Wi-Fi networks in more than 30 countries. Published reports say they captured private online information that might include general web browsing, passwords, personal emails and other data.
"I am demanding Google reveal any Wi-Fi data collection in Connecticut. If it occurred, the company should provide my office a full explanation, including what it gathered, where and why," Blumenthal said.
"Unauthorized surveillance of wireless network data is the dark side of the new Internet era -- and I will fight it,"Blumenthal said.