Apple has revealed that Samsung is being investigated by the U.S. Department of Justice.
The company announced the investigation in a filing with the U.S. International Trade Commission on Monday, saying that the "Department of Justice has opened an investigation into the manner in which Samsung has used -- or misused -- its declared-essential patents."
The Justice Department has not confirmed that and has stayed tight-lipped on the matter, but Dow Jones Newswires is reporting today, citing a source, that the investigation has been going on for months.
FOSS Patents' Florian Mueller was first to report on the investigation.
Essential, aka standard-essential, patents are handled differently than regular patents. When a company's patents are deemed standard and essential, it must offer them on a fair, reasonable, and nondiscriminatory (FRAND) basis. Apple has argued time and again that some of Samsung's wireless patents, which have been deemed standard-essential, are being offered on unfair terms, stifling competition.
In January, the European Union's European Commission announced that it had launched a formal investigation into whether Samsung was using its essential wireless patents as an anticompetitive tool, and thus violating a commitment it made to the European Telecommunications Standards Institute.
"Samsung sought injunctive relief in various Member States' courts against competing mobile device makers based on alleged infringements of certain of its patent rights which it has declared essential to implement European mobile telephony standards," the Commission said in January. "The Commission will investigate, in particular, whether in doing so Samsung has failed to honor its irrevocable commitment given in 1998 to the European Telecommunications Standards Institute (ETSI) to license any standard essential patents relating to European mobile telephony standards on fair, reasonable and non-discriminatory (FRAND) terms."
In other words, the European Commission wants to ensure Samsung isn't hurting competition by limiting competitors' use of technology that has been deemed essential in mobile products.
The Department of Justice has taken aim at standard-essential patents before. Earlier this year when it approved Google's acquisition of Motorola Mobility -- a move driven mainly be the search giant's desire to own more patents -- the Justice Department made clear that it would pay close attention to the handling of essential patents across the mobile market. The Samsung investigation might have been a response to that.
CNET has contacted both Apple and Samsung for comment on the investigation. We will update this story when we have more information.