"They've got to be able to do better than this", Lazowska told GeekWire this week.
Sandberg said the company began hearing rumors of Russian attempts to use the platform to spread propaganda around election day, but did not give a precise timeline about when the company began its review. The social media platform says that Russia-linked groups spent about $150,000 on political ads, including some promotions that mentioned either Donald Trump or Hillary Clinton by name.
Sandberg added that when official the investigation is complete, Facebook would release the information to the public and explain further about how it happened.
"Things happened on our platform in this election that shouldn't have happened", Sandberg said during an interview in Washington with the Axios news website.
Facebook found roughly 3,000 ads paid for by Russian operatives related to the 2016 campaign.
"We have a set of strict ads policies including limits on political ad targeting and prohibitions on targeting based on race and religion", a Google spokeswoman said, asked about the issue. "We'll continue to provide information".
But Sandberg acknowledged the company had erred in how it handled the issue of foreign interference a year ago.
The use of social media platforms was part of what USA intelligence agencies have concluded was a broader Russian effort to meddle in the election campaign, an allegation the Kremlin has denied.
They said Facebook lawyers have argued that turning over additional data could compromise its promise of privacy to its users. "And whenever you have [an] entity like the Russians who are purchasing ads in rubles or dollars through fake accounts, sowing seeds of racial tension and animosity and anti-immigrant sentiment and Islamophobia, we should all be concerned".