In the wake of the 2016 election, Instagram — known as the home of preening influencers, artfully arranged grain bowls and Icelandic vacation photos — somehow escaped much of the scrutiny of other social networks.

But two new reports suggest that may have been a mistake. The reports, conducted by independent groups and released by the Senate Intelligence Committee on Monday, concluded that Instagram — which is owned by Facebook — became a favored tool of Russian internet trolls after the 2016 election.

According to the reports, which were based on a trove of data provided by social media companies, Russia’s Internet Research Agency operated a vast network of accounts on Instagram that sought to infiltrate American identity groups, harden ideological divides and sow distrust in the American political system.

Much of the group’s activity was concentrated among several dozen large accounts, including one called @blackstagram_ and another called @american.veterans, both of which had more than 200,000 followers. Many of the group’s accounts targeted specific identity groups, including African-Americans, gun-rights supporters and anti-immigration activists.