South Korean police said they raided Google Seoul office today on suspicion that the company had illegally collected data on users.
Google has been preparing since late last year to launch its Street View service in South Korea and the data collection was related to the launch, police said.
The inquiry in one of Asia's most wired countries came as a fresh setback to Google, which already faces investigation over Streetview by the US Federal Trade Commission, a variety of probes overseas and class action lawsuits.
Google was not immediately available for comment.
"(The police) have been investigating Google Korea LLC on suspicion of unauthorised collection and storage of data on unspecified Internet users from Wi-Fi networks," the Korean National Police Agency said in a statement.
Google has said previously the data was accidentally collected by its cars and has grounded its Streetview cars globally.
Streetview is a technology featured in Google Maps and Google Earth that provides panoramic views from various positions along many streets in the world.
Google recently announced plans to resume its Streetview mappint in towns and cities around Ireland after discussions with data privacy regulators.
The company took the cars off the road in May and contacted data protection authorities when it was revealed that its cars had collected data sent over wireless networks in homes and businesses in the areas the cars were mapping.
The company claimed such data was gathered inadvertently.
The data was deleted and independently verified as having been destroyed.