A privacy agency in Britain is to re-open an investigation into whether Google broke any rules about personal information while it was gathering pictures and data for its internet Street-View service.
The Information Commissioner's Office investigated a sample earlier this year after it was revealed that Google had collected personal data during the project.
At the time, it said no "significant" personal details were collected.
But Google has since admitted that e-mails and passwords were copied.
Senior vice president Alan Eustace wrote on an official Google blog that the company was "mortified" to discover, after the initial investigation in May, that personal information had been collected.
Privacy agencies in other countries, including France, Germany and Canada, also investigated the information.
"It's clear from those [external] inspections that while most of the data is fragmentary, in some instances entire e-mails and URLs were captured, as well as passwords," Mr Eustace wrote.
"We want to delete this data as soon as possible and I would like to apologise again for the fact that we collected it in the first place.
The BBC reports Google's admission of more detailed data has now prompted further action by the ICO.
Google's director of privacy Alma Whitten said the company would work with the ICO to answer its "further questions and concerns".
She added that the data "has never been used in any Google product and was never intended to be used by Google in any way".