The Justice Department has begun issuing civil investigation demands, also known as CIDs, that will help its antitrust division find out if the deal that was made public by Yahoo and Google about a month ago is legal or not. The CIDS will supposedly be sent not only to Yahoo and Google, but to its competitors and other companies that could be hurt by the deal also.

Civil investigation demands are the equivalent of the subpoenas that are used in criminal trails and help the authorities collect information about a certain subject. A company that gets a CID is obliged to share the requested information with the Justice Department.

Yahoo and Google closed a deal last month according to which Google would have gained permission to put some of its search ads on Yahoo pages. Yahoo said that the move would bring $800 million in revenue, and that it would help the company boost its activity on segments of the internet ad market where Google does not hold an extremely powerful position.

The two companies have agreed to let a three and half month period for the authorities to investigate the deal before they put into practice. The fact that the Justice Department has started issuing the CIDs, could mean that its antitrust division has found something fishy about the partnership. However, the two companies consider that this is just a normal step of the investigation.

If the Justice Department will consider that something is wrong about the deal, Google and Yahoo might be called at the negotiation table to change some points of it. If this would not yield any results, a lawsuit against the two companies will be filled.