Google is being threatened with a $6 billion fine if it does not further change its search engine to meet European Union regulations.
The antitrust case claims Google is abusing its position as the dominant search engine by burying rivals positions in search.
"We have received complaints on the possible diversion of Internet traffic toward Google services which are not search services, so this is a possible third investigation concerning Google," said Joaquín Almunia, vice president of the European Commission and commissioner in charge of competition policy.
The news comes after Google's settlement proposal, announced in February, was rejected for the fourth time earlier in September.
If Google fails to meet the commission's expectations, "the logical next step is to move to a statement of objections," continued Almunia.
Almunia has come under scrutiny from critics of the investigation, who say Almunia is playing into Google's hands by giving them so many chances to renegotiate.
Initially Almunia backed the proposal. However, following criticism from top politicians in Europe, the deal collapsed. The final decision in the case will now fall to Almunia's successor, former Danish economy minister, Margrethe Vestager. Almunia is scheduled to leave office in October.
It is unclear what Vestager thinks of the case. However, she stressed in an interview that fair competition in the digital economy was extremely important and very high on the agenda of the European Commission.
"We have to make sure that there is a high degree of security in relation to personal data, that there is a high degree of confidence from the people that the competition rules and regulations on market fairness are actually being enforced," Vestager said.
Almunia also drew parallels between the Google case and a long investigation into Microsoft, which ended in $2.8 billion in fines for the company.
"Microsoft was investigated for 16 years, which is four times as much as the Google investigation has taken and there are more problems with Google than there were with Microsoft," he said (subscription required).
Some politicians even went as far as to suggest that a forced break-up of Google should take place because of the vast power that the company has. Almunia, however, disagreed.
"I would tell you one thing, as a German friend," said Almunia. "The day I [hear] that the railways will accept unbundling, electricity companies will accept unbundling, and we will discuss [unbundling] with telecom operators and others...let's discuss unbundling Google, but not before."
It is also possible that the EU will launch a similar investigation into Google's mobile operating system, Android, which has been the subject of a number of complaints.