Washington (CNN)President Donald Trump requested the FBI investigate how the Obama administration was involved in Russian meddling in the 2016 -- questioning why Congress and federal investigators aren't probing how the Democratic administration handled certain issues.
Here's what Congress is investigating from the Obama administration
"Question: If all of the Russian meddling took place during the Obama Administration, right up to January 20th, why aren't they the subject of the investigation?" Trump tweeted. "Why didn't Obama do something about the meddling? Why aren't Dem crimes under investigation? Ask Jeff Sessions!"
Trump's tweet is his latest attack on his attorney general over Russia and special counsel Robert Mueller's probe, which returned 13 indictments against Russians last week for their alleged role in meddling in the 2016 election.
The House and Senate Intelligence Committees have interviewed numerous Obama administration officials about the election meddling, though those efforts focus on reviewing the intelligence community's assessment of Russian election interference and preventing future Russian attempts — and not "Democratic crimes" as Trump was suggesting.
But there are several investigations in Congress currently probing Obama administration incidences, including several with ties to Russia.
Here's a look at all the things Congress is still investigating during the Obama administration:
House Intelligence Chairman Devin Nunes and Oversight Chairman Trey Gowdy announced last October that they were going to launch an investigation into an Obama-era Uranium deal that some have linked to former Secretary of State Hillary Clinton.
The Republican-led probe from Nunes, a California Republican, and Gowdy, a South Carolina Republican, concerns a 2010 uranium deal that was struck between the US and Russia while Clinton was secretary of state.
Trump and other Republicans have accused the Russian uranium company of donating to the Clinton Foundation in an effort to sway Clinton to sign off on the deal, though the allegations are unproven. The deal was approved through an inter-agency process, not just the State Department.
But the matter is being evaluated at the Justice Department, too. Sessions last year said he would consider appointing a second special counsel as many Republicans have demanded, as he asked senior federal prosecutors to "evaluate certain issues" presented by House Republicans, including alleged ties between the Clinton Foundation and the sale of Uranium One.
House Republicans are preparing to ask former FBI Director James Comey to testify as part of the Republican-led probe into the FBI and Justice Department handling of the Clinton email investigation.
Comey's testimony, if he appeared, would raise the stakes of the joint Judiciary and Oversight Committee investigation into the decision not to charge the 2016 Democratic presidential nominee over classified emails on her private server -- and the rare step for Comey to publicly announce Clinton would not be charged.
Several Republicans told CNN that Comey is a key witness for the investigation, although no timetable has been set for his testimony. So far the committee has interviewed former Deputy FBI Director Andrew McCabe and Comey's chief of staff, James Rybicki, as part of the House committees' joint probe.
A series of text messages exchanged between top FBI employees referring to then-candidate Trump as an "idiot" and other insults, while fearing his potential victory as "terrifying," were released to lawmakers last December.
Before the texts were released, reports surfaced that special counsel Robert Mueller had removed Peter Strzok, one of the FBI's top Russian counterintelligence experts, from his team after an internal investigation by the Justice Department's inspector general uncovered politically tinged messages exchanged with FBI lawyer Lisa Page.
Throughout the primary season in 2016, Strzok and Page appeared to dread a Trump victory, according to the messages reviewed by CNN.
House and Senate investigators on multiple committees have received the text messages from the FBI, including a second batch sent last month. Thousands of messages that initially appeared to have been deleted have been recovered and will also be sent to the Hill panels soon.
With Trump's approval, House Republicans released a disputed GOP intelligence memo that alleges FBI abuses of its surveillance authority earlier this month.
The memo, which was led by Nunes, alleges that the FBI failed to tell the FISA court that the opposition research dossier on Trump and Russia written by ex-British intelligence office Christopher Steele was funded through Hillary Clinton's campaign and the Democratic National Committee. It also charges that McCabe told the committee the October 2016 surveillance warrant for former Trump campaign foreign policy adviser Carter Page wouldn't have been granted without the dossier, though Democrats say that's skewing his testimony.
The memo has been highly disputed on the committee, but conservatives have pointed to it to charge that the Obama administration was spying on the Trump administration through the FISA process.
A criminal referral of Steele to the Justice Department, which was sent by Senate Judiciary Chairman Chuck Grassley and Sen. Lindsey Graham and partially declassified by the FBI earlier this month, also alleges that Steele's dossier was misused by the FBI in obtaining the warrant on Page.