The odds of an antitrust showdown with Google rose on Thursday with reports that the US Federal Trade Commission hired a veteran outside attorney known for winning cases to handle the investigation.

Former Justice Department prosecutor Beth Wilkinson was brought in to head the team looking into whether Google abused its dominance in online search, according to media accounts during a visit here by the FTC chief.

Wilkinson's formidable legal track record includes being a lead prosecutor on the team that convicted Timothy McVeigh in connection with the bombing of a federal building in Oklahoma City in 1995.

US regulators last year launched a probe into Google's lucrative search and advertising business in a move that could pose the most serious legal challenge yet to the Internet giant.

The Mountain View, California-based company confirmed the FTC inquiry in a blog post at the time and expressed confidence it could withstand the scrutiny.

Google said in a Securities and Exchange Commission filing last year that it received a subpoena from the FTC "relating to a review by the FTC of Google's business practices, including search and advertising."

As it has grown from a scrappy startup into an Internet titan, Google has branched out into various businesses including online mapping, shopping and travel and providing operating systems for mobile phones and tablet computers.

But Google makes most of its money from search-related advertising and that is why an FTC investigation targeting its core business is seen by analysts as a potentially serious risk to the company.

Google has drawn increasing scrutiny from US and European regulators as it has grown over the years into an Internet powerhouse.