Donald Trump's legal problems appear to have escalated significantly on Thursday with federal charges over the retention of top secret documents, but investigators aren't done yet.The former president faces a string of inquiries in various states and venues as he campaigns for a second term in the White House. He's already been charged in a 34-count indictment in New York in a hush money case. The others include federal and state investigations into his efforts to overturn his loss in the 2020 election and a civil case that threatens his ability to ever again do business in New York.Trump, a Republican, has denied any wrongdoing and says he is being targeted by Democrats trying to keep him from reclaiming the presidency in 2024.Here's a look at the top probes:Hush money schemeTrump became the first former U.S. president in history to face criminal charges when he was indicted in New York in March on state charges stemming from hush money payments made during the 2016 presidential campaign to bury allegations that he had extramarital sexual encounters.He pleaded not guilty to 34 felony counts of falsifying business records. Each count is punishable by up to four years in prison, though it's not clear if a judge would impose any prison time if Trump is convicted.Video below: Legal expert analyzes Trump indictment, arraignment in hush money caseThe counts are linked to a series of checks that were written to his lawyer Michael Cohen to reimburse him for his role in paying off porn actor Stormy Daniels, who alleged a sexual encounter with Trump in 2006, not long after Melania Trump gave birth to their son, Barron. Those payments were recorded in various internal company documents as being for a legal retainer that prosecutors say didn't exist.The former president is next set to appear in court on Dec. 4, two months before Republicans begin their nominating process in earnest.GeorgiaFor over two years, Fulton County District Attorney Fani Willis has been investigating whether then-President Donald Trump and his allies illegally meddled in the 2020 election in Georgia.She wrote in a letter to the county sheriff that she expects to announce any charging decisions between July 11 and Sept. 1. In a separate letter to a county Superior Court judge, she suggested that any indictments would likely come in August.The Democratic district attorney's investigation began shortly after the release of a recording of a Jan. 2, 2021, phone call between Trump and Georgia Secretary of State Brad Raffensperger in which the then-president suggested that Raffensperger could "find 11,780 votes" — just enough to overtake Democrat Joe Biden and overturn Trump's narrow loss in the state.But the investigation's scope broadened considerably after that, and Willis convened a special grand jury to hear testimony from witnesses including high-profile Trump allies, such as attorney Rudy Giuliani and Sen. Lindsey Graham of South Carolina, and high-ranking Georgia officials, such as Raffensperger and Gov. Brian Kemp.Prosecutors advised Giuliani and Georgia Republicans who served as fake electors that they were at risk of being indicted. The fake electors signed a certificate asserting Trump had won the election and declaring themselves the state's electors, even though Biden had won the state and Democratic electors had already been certified.A court filing in early May indicated that Willis had reached immunity deals with at least eight fake electors, suggesting they may be cooperating with authorities.The foreperson on the special grand jury indicated publicly that the panel had recommended multiple indictments. It's now up to Willis to decide whether to convene a regular grand jury and pursue criminal charges in the case.Trump and his allies have denied wrongdoing, and he has repeatedly described his phone call to Raffensperger as "perfect."2020 election and Capitol riotSpecial counsel Jack Smith, who was appointed by Attorney General Merrick Garland to investigate Trump's handling of classified documents, has also been leading a team probing efforts by Trump and his allies to overturn the election that he falsely claimed was stolen.Federal prosecutors have been especially focused on a scheme by Trump allies to put forth a slate of fake presidential electors in key battleground states who falsely declared that Trump, not Biden, had won the 2020 election. They have issued subpoenas to a number of state Republican Party chairs.Federal prosecutors have brought multiple Trump administration officials before that grand jury for questioning, including former Vice President Mike Pence. In a sign of the wide-ranging nature of the investigation, election officials in multiple states whose results were disputed by Trump have received subpoenas asking for past communications with or involving Trump and his campaign aides.A House committee that investigated the Jan. 6 attack on the Capitol recommended that the Justice Department bring criminal charges against Trump and associates who helped him launch a wide-ranging pressure campaign to try to overturn his 2020 election loss.New York civil casesNew York Attorney General Letitia James has sued Trump and the Trump Organization, alleging they misled banks and tax authorities about the value of assets including golf courses and skyscrapers to get loans and tax benefits.That lawsuit could lead to civil penalties against the company if James, a Democrat, prevails. She is seeking a $250 million fine and a ban on Trump doing business in New York. Manhattan prosecutors investigated the same alleged conduct but did not pursue criminal charges.A civil trial is scheduled in state court for October.Video below: How key piece of Trump deposition likely led jury to find him liable of sexual abuseIn a separate civil case in federal court in New York, Trump was found liable in May of sexually abusing and defaming former magazine columnist E. Jean Carroll in the mid-1990s. The jury rejected Carroll's claim that Trump had raped her in a dressing room.Trump was ordered to pay $5 million to Carroll. He has appealed and has adamantly denied her accusations.