Prosecutors with the U.S. Justice Department are reportedly investigating claims that eBay employees took confidential info from Craigslist to use in a service that would compete with it.

Reuters reports that it has obviated a copy of a grand jury subpoena as an old civil dispute turns into a criminal investigation. Reuters quotes an eBay spokeswoman as saying in an email, “EBay believes that Craigslist’s allegations against eBay are without merit. We will continue to vigorously defend ourselves, and we will aggressively pursue our claims against Craigslist.”

She also said eBay would cooperate in any inquiry related to the dispute. Bloomberg reports:

The Sept. 7 grand jury subpoena of Craigslist seeks information pertaining to “incidents where EBay employees engaged in alleged criminal activities and misconduct focused around the misappropriation of proprietary/confidential information from Craigslist.”

The incidents include a February 2005 request by Pierre Omidyar, EBay’s chairman and founder, for information about Craigslist’s approach to adding new cities and advance notice of plans to launch new cities, according to the subpoena.

eBay’s rival site would be eBayClassifieds.com.

eBay purchased a 28% stake in Craigslist all the way back in 2004.