The investigation could be the one that in a recent filing with the U.S. Securities and Exchange Commission in which the search giant vaguely said it was being investigated by the DOJ for the use of Google advertising by certain advertisers. The company said it had set aside US$500 million for a potential settlement.

The Journal, citing unnamed sources, said Google was close to settling the investigation, which alleged it made hundreds of millions of dollars from the online pharmacies. The DOJ alleged Google had made hundreds of millions of dollars from the online pharmacies and examined whether the company knew the online pharmacies broke U.S. laws, according to the report.

The State of Rhode Island Office of the Attorney General and the Food and Drug Administration conducted the investigation, according to the report. The Rhode Island attorney general's office did not reply to a request for comment made after its regular business hours. The FDA doesn't comment on investigations, according to an agency spokeswoman.

Google declined to comment.

Google has tried to block online pharmacies that illegally sell prescription drugs from using its ad network. Last year, in a California court for misusing AdWords and violating its terms of use.