FIRST ON FOX: ActBlue co-founder Matt DeBergalis pleaded the Fifth Amendment during his closed-door deposition before three key House committees, sources familiar with the matter told Fox News Digital.

The Committee on House Administration, House Oversight Committee, and House Judiciary Committee are conducting a joint investigation into ActBlue, a massive fundraising platform for Democrats, over allegations that lax fraud prevention standards may have allowed foreign donations to seep into U.S. campaigns.

DeBergalis' deposition, which was scheduled for Thursday morning, lasted less than half an hour. FOX News saw DeBergalis entering and exiting the committee room within roughly 25 minutes.

Fox News Digital reached out to ActBlue for comment. Fox News Digital also reached out to the majority and minorities of each of the three committees.

Pleading the Fifth Amendment is not evidence of wrongdoing. ActBlue has repeatedly denied running afoul of the law during the course of Republicans' probe.

This story is breaking and will be updated...