Google on Thursday blamed Federal Communications Commission for dragging out an investigation into Google's "Street View" online mapping service gathering data from private wireless hotspots.

Google detailed in a 17-page letter to the FCC how fault for delay rested with the commission but said that the Internet giant would pay a $25,000 penalty demanded for purportedly stalling the probe.

"While Google disagrees with the premise of the (FCC) notice and many of its factual recitals, Google has determined to pay the forfeiture proposed in the notice in order to put this investigation behind it," the company said.

The FCC enforcement bureau on April 13 dropped its Street View investigation, saying it could not accuse Google of breaking US law but wanted the company to be penalized for not cooperating quickly enough.

"Google had every interest in cooperating and did so fully at all times on a timetable discussed and agreed to by the Commission," stated the letter signed by Google counsel Ashton Johnston.

"Google shares the FCC's concern about the protracted nature of the investigation, but notes that most of the delays resulted from internal FCC process."

The FCC began the investigation in late 2010 after Google announced that Street View cars taking photographs of cities in more than 30 countries had inadvertently gathered data sent over unsecured Wi-Fi systems.

The Federal Trade Commission and US Justice Department had already opened and closed Street View investigations, according to Google.

Information sucked up by passing Street View cars included passwords, emails, and other data that was being transmitted wirelessly over unprotected routers, according to the FCC.

Google has since stopped the collection of Wi-Fi data, used to provide location-based services such as driving directions in Google Maps and other products, by Street View cars.

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.

The FCC contended that Google ignored requests for internal information such as emails related to Street View data collection and the names of employees who authorized or reviewed it.

"For many months, Google deliberately impeded and delayed the bureau's investigation by failing to respond to requests for material information," FCC enforcement bureau chief Michele Ellison said in a written report.

"Google's level of cooperation with this matter fell way short of what we expect and require," Ellison said while backing the decision to require the company to forfeit $25,000 as punishment.