US state attorneys pressed Google to name workers who wrote the "snooping" code that captured personal data from wireless networks while Street View cars mapped streets.
"Google's responses continue to generate more questions than they answer," said Connecticut Attorney General Richard Blumenthal, part of a 38-state coalition investigating whether the search giant broke US law.
Blumenthal in June launched the probe of "Google's deeply disturbing invasion of personal privacy," which has drawn ire and scrutiny in an array of countries.
On Wednesday, he said he wants Google to tell whether testing of Street View software prior to its use revealed it captured data from wireless networks and to finger the engineers that wrote the code.
He also wanted to know specific spots where data was collected and what Google did with information it gathered.
"We are asking Google to identify specific individuals responsible for the snooping code and how Google was unaware that this code allowed the Street View cars to collect data broadcast over Wi-Fi networks," Blumenthal said.
"We will take all appropriate steps, including potential legal action if warranted, to obtain complete, comprehensive answers."
The Mountain View, California-based search and advertising titan is facing lawsuits and investigations in a number of countries in connection with private wireless data collected by Street View cars.
Google executives including co-founder Sergey Brin said the collection of wireless data was unintentional and a blunder.
Street View cars "will no longer collect any Wi-Fi information at all, but will continue to collect photos and 3D imagery as they did before," Google vice president of engineering Brian McClendon said earlier this month in a blog.
He said Wi-Fi data collection equipment has been removed from its cars.
Google has apologized repeatedly for what it maintains was a "mistake."
Street View, which was launched in 2006, lets users view panoramic street scenes on Google Maps and take a virtual "walk" through cities such as New York, Paris or Hong Kong.
Explore further: Google to resume taking 'Street View' photos next week