On Tuesday, a CNN report seemed to confirm President Donald Trump’s suspicions that the Obama administration issued surveillance on top members of Trump’s campaign staff. CNN reported that Paul Manafort, Trump’s former campaign chairman, was indeed spied upon during President Obama’s tenure.

While the story does seem to confirm Trump’s allegations, the truth proved rather complicated. Here are five things to know about the developing story.

1. Manafort was wiretapped, and maybe Trump was, too.

On Tuesday, CNN reporters Evan Perez, Shimon Prokupecz, and Pamela Brown reported that the federal government did indeed snoop on Trump campaign chairman Paul Manafort.

“US investigators wiretapped former Trump campaign chairman Paul Manafort under secret court orders before and after the election, sources tell CNN, an extraordinary step involving a high-ranking campaign official now at the center of the Russia meddling probe,” the writers reported.

To make matters worse, the spying continued into early this year, when Manafort was known to be speaking with President Trump.

CNN’s sources suggested that some of the evidence “sparked concerns among investigators that Manafort had encouraged the Russians to help with the campaign,” but that the evidence of Russian collusion remained inconclusive.

Earlier reports suggesting that a court working under the auspices of the Foreign Intelligence Service Act (FISA) ordered wiretapping of Trump campaign officials seemed fully vindicated by the CNN bombshell, which reported that a FISA court authorized an order to spy on Manafort.

But at this point, the news becomes less rosy for Trump supporters. The original FISA order began when Manafort became the subject of an FBI investigation that began in 2014. More on this later.

The surveillance was paused last year for lack of evidence, but then resumed after a new FISA warrant was obtained. This second warrant covered an unspecified time leading into early this year.

FBI interest reportedly deepened last fall because of intercepted communications between Manafort and suspected Russian operatives. The FBI conducted a search of a storage facility belonging to Manafort.

While Manafort resigned from the Trump campaign in August of last year, after only five months on the campaign, he continued to speak with Trump after the Republican took office. They kept speaking to one another after the FBI investigation into Manafort was public knowledge, and only stopped when lawyers insisted they do so.

Manafort has denied that he ever “knowingly” communicated with Russian intelligence operatives during the election and has also denied participating in any Russian efforts to “undermine the interests of the United States.”

2. Why the surveillance started.

The FBI first became interested in Manafort in 2014, as an outgrowth of a U.S. investigation into Viktor Yanukovych, the former Ukrainian president whose pro-Russian regime was removed from power amid street protests.

Last August, a secret ledger from Yanukovych’s Party of Regions was unearthed by Ukraine’s National Anti-Corruption Bureau. The ledger listed $12.7 million in cash payments for Manafort.

“Paul Manafort is among those names on the list of so-called ‘black accounts of the Party of Regions,’ which the detectives of the National Anti-Corruption Bureau of Ukraine are investigation,” the bureau released in a statement.

In addition to ledgers like this one, criminal prosecutors in Ukraine are also investigating a group of offshore shell companies that helped fund the former president’s lavish lifestyle, including a palace with a private zoo, golf course, and tennis court.

Investigators have probed roles played by Manafort’s firm, but also other shady U.S. political actors like the Podesta Group and Mercury, LLC.

The basis for the 2014 case against Manafort hinged on the failure of such lobbying firms to register under the U.S. Foreign Agents Restoration Act. Each of the firms involved filed retroactive registrations this year.

Justice Department prosecutors eventually concluded that there wasn’t enough evidence to bring charges against Manafort or other U.S. subjects in the probe. The FBI and Justice Department are required to seek renewed FISA authorization.

CNN reported that when Manafort took the reins as Trump’s full campaign chairman in May, the FBI was no longer listening. His role in the campaign did not stop the monitoring, but rather the FBI’s determination that there was not enough evidence in the Ukraine case.

It is unclear as to whether or not Manafort had a residence in Trump Tower during the time of the first period of surveillance. Since the case had nothing to do with the Trump campaign and began in 2014, it seems likely to have been at least mostly above board.

Trump hired Manafort for his expertise with political conventions — he helped Ronald Reagan secure the 1980 Republican nomination, and his success with Yanukovych in Ukraine also spoke to Manafort’s acumen as a political operator. Even so, Trump might have been better served looking elsewhere.

3. The second round of spying.

The FBI’s second round of surveillance on Manafort may prove more problematic, however. By the time Manafort left the campaign in August, the FBI had reportedly noticed odd connections between Trump associates and Russian operatives. The CIA also suspected that Russian President Vladimir Putin had ordered his intelligence agencies to conduct an operation to meddle in the 2016 election.

With this in mind, FBI surveillance teams secured a second FISA warrant to monitor Manafort. FISA operations are kept strictly secret, and speculation has run rampant as to whether or not Manafort or other Trump associates were under surveillance during the final stages of the 2016 campaign.

Manafort has a residence in Trump Tower, which lent a deeper sense of unease to the report that the former campaign chairman was again wiretapped late last year.

In addition to the Trump Tower residence, Manafort has a home in Alexandria, Va., which FBI agents raided in July of this year.

The FBI also spied on Carter Page, a campaign associate whom Trump identified as a national security adviser. Like in the case of Manafort, the FBI obtained a FISA warrant on Page in 2014. U.S. intelligence agencies suspected that Russian spies tried to cultivate Page as a U.S. asset for their influence.

4. Trump’s accusation.

In March, President Trump accused Obama of wiretapping the phones in Trump Tower.

“Terrible! Just found out that Obama had my ‘wires tapped’ in Trump Tower just before the victory. Nothing found. This is McCarthythism!” the president tweeted. “How low has President Obama gone to tapp [sic] my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!”

Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism! — Donald J. Trump (@realDonaldTrump) March 4, 2017

Reports of Obama administration officials using FISA court requests to monitor Trump campaign officials trace back to the eve of the election. HeatStreet reported that a first FISA request was denied in June, but another was granted in October.

The second request was granted “after evidence was presented of [the private server in Trump Tower], possibly related to the Trump campaign, and its alleged links to two banks; SVB Bank and Russia’s Alfa Bank.” The report did not specify that phones in Trump Tower had been tapped, only that the server was in the tower.

National Review‘s Andrew McCarthy argued that “it is rare and controversial to use FISA wiretaps in criminal prosecutions.” He suggested this case might be an example of “the government pretextually using its national-security authority to continue a criminal investigation after determining it lacked evidence of crimes.”

The CNN report did not specify when the second FISA authorization for spying on Manafort started, but the HeatStreet report gave an October time frame, which should be particularly concerning, coming shortly before a presidential election.

5. Obama’s denial.

Shortly after Trump’s accusation, Obama spokesman Kevin Lewis denied any allegations of using FISA requests to undermine the Republican nominee shortly before the 2016 election.

A cardinal rule of the Obama Administration was that no White House official ever interfered with any independent investigation led by the Department of Justice. As part of that practice, neither President Obama nor any White House official ever ordered surveillance on any U.S. citizen. Any suggestion otherwise is simply false.

This declaration was so disingenuous as to be Orwellian.

First, as National Review‘s David French pointed out, the FISA surveillance process involves a FISA court “ordering” such spying, while the Justice Department (not Obama or the White House) would represent the administration before that court. The issue is “whether the Obama Justice Department sought such surveillance authorization from the FISA court and whether … the White House was aware of or complicit in the decision to do so.”

The CNN report confirms that the Obama DOJ did request surveillance on Manafort, and it seems unlikely Obama would not know about it.

Second, Obama has ordered surveillance against American citizens, even having them killed in drone operations. David French argued that “the notion that Obama would never have an American subject to surveillance is absurd.” Indeed, as he left office, Obama gave the National Security Agency (NSA) broad powers to spy on Americans.

Finally, FISA investigations are significantly different from criminal investigations. They aim to gather information about the spying attempts of foreign powers. While this is the president’s prerogative, “it would be a scandal of Watergate dimension if a presidential administration sought to conduct, or did conduct, national-security surveillance against the presidential candidate of the opposition party.”

This recent CNN report makes clear that the Obama administration did indeed order surveillance on one of Trump’s major staffers. The HeatStreet report suggests that the FISA surveillance order did not come until October, two months after Manafort left the Trump campaign. But this is still a bombshell, because Manafort and Trump remained in contact until early this year.

The Trump-Russia investigation continues on apace. One likely underreported angle will be the extent to which the Obama administration ordered surveillance on members of the opposing party’s political campaign right before the presidential election. This CNN report suggests that the Obama “Watergate” bombshell is only just beginning to see the light of day.