A bipartisan coalition of state attorneys is said to be preparing a new antitrust investigation into several of the world’s biggest tech companies. The news was first reported by the Wall Street Journal, which cited unnamed sources.

Following similar probes from the likes of the Department of Justice, Federal Trade Commission and House Judiciary Committee, these state attorneys will reportedly begin investigating Amazon, Apple, Facebook, and Alphabet Inc., the parent company of Google, for antitrust practices aimed at reducing competition. None of the companies have commented on the report.

There are potentially 20 state attorneys involved in this coming investigation. It's unclear which attorneys general are involved, though the group is expected to include both Democrats and Republicans.

“What you’re seeing is more AGs of both parties trying to pursue this issue,” Mississippi Attorney General Jim Hood, a Democrat running for governor, said in a June interview with the Journal.

Reports indicate that this state investigation could potentially merge with the preexisting DOJ probe, as a group of a dozen state attorneys reportedly met the department in July to discuss the issues concerning them.

For their parts, the companies targeted in this inquiry have strenuously denied any sort of antitrust behavior.