One of the most audacious projects ever to come out of Google was the plan to photograph and map the inhabited world, one block at a time. But a report over the weekend from federal regulators has rekindled questions over exactly what the company was doing — questions the search giant has spent years trying not to answer.

The Federal Communications Commission censured Google for obstructing an inquiry into the Street View project, which had collected Internet communications from potentially millions of unknowing households as specially equipped cars drove slowly by.

But the investigation, described in an interim report, was left unresolved because a critical participant, the Google engineer in charge of the project, cited his Fifth Amendment right and declined to talk. It is unclear who else at Google might have known about the data gathering, or when they might have known.

Google maintains that the data gathering was unauthorized, according to a person with knowledge of the matter, but the engineer is maintaining that other people at the company knew about it.