And, a significant discovery has been that the source of the funding for the ads, appears to be different from those identified by Facebook.
All three firms are expected to appear on November 1 in an open Senate Intelligence Committee hearing on the rising evidence that they were covertly manipulated in a campaign to help Donald Trump win the presidency.
Twitter and Facebook have said Russian Federation bought ads and had accounts on their platforms. The news about the Instagram ads was released last Friday in a blog post from Facebook's VP of policy and communications Elliot Schrage and was the first notification that Russian-bought ads ran on more than Facebook's signature platform.
As with other tech giants, Google has previously downplayed the likelihood of Russian involvement on its platforms ahead of last year's U.S. presidential elections. The company said it found 450 accounts and about $100,000 was spent on the ads.
Google's products include YouTube, Gmail, and the company's DoubleClick ad network. Since Google is the world's largest online advertising business and YouTube is the world's largest online video site, there were always good chances that Russian operatives exploited the platforms to forward their propaganda. The social network allows advertisers to target its audience with more specificity than Google, including users with a wide range of political leanings.More news: Google: Pixel 2 still has headphone jack - if you count USB-C
More news: USA to boost military personnel in Puerto Rico: senator
More news: Five toddlers burned alive in arson attack on nursery
Google is investigating claims that shadowy Russian agents paid tens of thousands of dollars to advertise on its platforms in a bid to influence the U.S. election. This was a broad search, including, for instance, ads bought from accounts with US IP addresses but with the language set to Russian - even though they didn't necessarily violate any policy or law. Others were about the USA immigration policy, an apparent attempt to promote division among the American people.
Twitter, meanwhile, has been shown to be a dense thicket of easily faked accounts and news items that allowed alleged Russian operatives to pump out politically divisive and anti-Clinton tweets.
It has turned the ads over to congressional panels investigating Russian involvement in the election. "In this part of our review, we found approximately $US50,000 in potentially politically related ad spending on roughly 2200 ads".
Google is working with Jigsaw, a think tank owned by its parent company, Alphabet.
For Facebook and now Google, the ongoing controversy and multiple investigations by lawmakers into the problem further undermines their standing at a time when there are growing questions by advertisers around a lack of transparency in the digital media supply chain.