Facebook probed suspicious content supporting 2020 presidential contender Sen. Bernie Sanders (I-VT), but the social network was unable to determine whether pro-Trump or Russian actors took part in the coordinated inauthentic behavior. According to The Wall Street Journal, the company reportedly reviewed data from at least one outside researcher that showed inauthentic content backing Sanders being posted on the platform in the past several months. Some of Facebook’s leadership has been briefed on the investigation—which is not typical for the company. It’s unclear whether the probe is still ongoing. “We investigate each credible claim we receive, just as we did in this instance when an outside researcher contacted us,” Facebook spokesman Andy Stone said. “To date, we have not been able to substantiate the researcher’s claims and we have not been notified by the intelligence community.” This comes after the Sanders campaign was reportedly informed that Russia was attempting to help him in the 2020 election as part of their meddling effort, though its unclear whether Facebook’s internal probe is related to the Sanders briefing.