Connecticut's attorney general, who is leading a 37-state probe of Google's collection of data from private Wi-Fi networks, asked the Internet search leader on Wednesday if it had tested the software before using it.
Attorney General Richard Blumenthal also asked for the names of the people responsible for the software, which Google has said was supposed to only use Wi-Fi to determine location, not to download personal email and other data.
"We will take all appropriate steps — including potential legal action if warranted — to obtain complete, comprehensive answers," he said in a press statement.
Google has said the data were accidentally collected by "Street View" cars, well known for crisscrossing the globe and taking panoramic pictures of city streets, which the company displays in its online maps product.
In his letter to Google, Blumenthal asked whether the software in the Street View cars had been tested to determine if consumer data would be collected, how many states were affected and who inserted the data collection code into the Street View software.
Google is cooperating with authorities looking at the issue, said spokeswoman Christine Chen.
"As we've said before, it was a mistake for us to include code in our software that collected payload data, but we believe we did nothing illegal," said Chen in an e-mail statement.
Blumenthal, who asked for answers to the questions by Friday, also said that 37 states and the District of Columbia were behind his effort.
Google executives were scheduled to meet Friday with Blumenthal and representatives of other state attorneys general, according to a source with knowledge of the situation who is not authorized to speak about the meeting.
The meeting was set up before Blumenthal issued the most recent round of questions on Wednesday.
It was first revealed that Street View cars were collecting wireless data in April. After an audit requested by Germany, Google acknowledged in May that it had been mistakenly collecting samples of personal data for years.
The company already faces an informal investigation over the matter by the U.S. Federal Trade Commission, a variety of probes overseas, and class action lawsuits.
The company says it uses the location of Wi-Fi networks to enhance location-based services on smartphones.
After the discovery of the error, Google grounded its Street View cars globally. It has said recently that the cars, which no longer collect Wi-Fi data, would resume work in Ireland, Norway, South Africa and Sweden.