(CNN) President Donald Trump's former campaign chairman is facing new revelations about two key issues: his personal finances and his past political consulting in Ukraine.

Property records reviewed by CNN show that Paul Manafort and his wife bought $17 million worth of real estate in New York City, Palm Beach, Fla., and the Washington, D.C., suburbs between 2006 and 2012 when he was working with Ukrainian politicians and with a Russian billionaire.

Records also show that since 2015, Manafort borrowed $22 million against his properties -- which came as he faced financial problems resulting from failed business dealings with his son-in-law.

Separately, an Associated Press story Wednesday said Manafort received two "off-the-books" payments worth $1.2 million in the late 2000s from a pro-Russia political party in Ukraine for which he consulted.

Manafort's finances and consulting work are drawing attention as Ukrainian officials try to determine whether he received improper payments as part of a corruption case into ex-President Victor Yanukovych—Manafort's former client. US authorities also are investigating possible Ukrainian corruption and any role Manafort may have played in Russia's meddling in the 2016 presidential election.

Manafort strongly denies any wrongdoing in connection with his work for Trump and foreign officials. He has offered to testify before Congressional committees investigating Russia's election interference.

Manafort's finances

Manafort's decade of work with Ukrainians and a Russian industrialist coincided with a buying spree of high-priced real estate.

From 2006 to 2012, records show, Manafort and his wife Kathleen spent $12 million on four residential units in New York City, including a $3.7-million apartment in Trump Tower. They also bought a $2.7-million condominium in Alexandria, Va., and a $1.5-million house home in Palm Beach, Fla.

More recently, the Manaforts became borrowers, receiving $13 million in loans between 2015 and 2017 that were secured by three of their recent New York purchases.

The Manaforts had paid cash for all three properties, meaning the recent mortgages are loans against assets they fully own, according to New York City property records.

In 2016, they borrowed at least $9.5 million against a summer home they have owned for years in the Hamptons, documents show.

Manafort said in a statement the loans are nothing special, and that borrowing against real estate is "common when the properties increase in value."

"There is nothing out of the ordinary about them," Manafort added, "and I am confident that anyone who isn't afflicted with scandal-fever will come to the same conclusion."

Manafort would not discuss the purpose of the loans, but they came as his business dealings with his son-in-law faced financial turmoil.

Jeffrey Yohai, who is married to Manafort's daughter Jessica, joined with his father-in-law and others to invest in properties around Los Angeles.

Yohai's companies, which purchased the properties, are now seeking bankruptcy protection, court records show. Yohai filed for Chapter 11 bankruptcy protection in December for three companies, and another was filed but later dismissed.

In a February affidavit in the case, Manafort said he is paying for Yohai's bankruptcy attorney -- "to protect my existing investment in the properties."

Yohai owes Manafort $2.7 million for a loan that Yohai used to buy a property in the ritzy LA neighborhood of Bel-Air, according to bankruptcy records. Yohai also owes Manafort, his wife Kathleen and his daughter Jessica $780,521 on another LA property acquired by Yohai.

Black ledger connections

The AP story Wednesday revived allegations that surfaced in August -- and led to Manafort's campaign ouster -- of a so-called "black ledger" in Ukraine that lists 22 suspicious cash payments worth $12.7 million designated for Manafort.

Officials in Ukraine and the US are investigating alleged corruption under Yanukovych, the former Ukrainian president who hired Manafort as a consultant, including payments listed in the ledger."

CNN revealed in March a $750,000 invoice found by Ukrainian investigators that matches a payment listed in the black ledger. The invoice, for computer equipment, appeared to bear Manafort's signature, though CNN could not verify its authenticity.

Manafort said the signature was forged and denied receiving illicit payments -- a statement he repeated following the AP story that said he had received a $750,000 payment and a $455,000 payment, matching entries in the ledger.

Manafort spokesman Jason Maloni said he wasn't sure if Manafort received the $1.2 million, but that if he did, it was for consulting work.

"No one has produced any evidence that the payments were for anything other than legitimate political consulting that Paul was openly doing during this period," Maloni said.

Ukraine's anti-corruption bureau has cautioned that the appearance of Manafort's name in the ledger "does not mean he actually got the money."

Maloni also noted that the AP said Manafort received the payments through wire transfers into his U.S. bank account. That contradicted original reports saying the ledger listed "cash payments," Maloni said.

Reports about the ledger led to Trump removing Manafort as his campaign chairman in August after just five months with the campaign.

On Wednesday, sources told CNN that Manafort is expected soon to resolve some questions about his work in Ukraine by registering with the Justice Department as a "foreign agent"-- a process required for lobbyists that represent foreign entities in the U.S.

Other scrutiny

The questions about Manafort's business in Ukraine come as the US Congress is investigating whether he was involved with Russia's meddling in the 2016 election.

Manafort has volunteered to speak to the House and Senate committees in charge of the investigation, but that's not imminent.

Senator Mark Warner of Virginia, the ranking Democrat on the Senate intelligence committee, has indicated that the committee will wait until its staff reviews raw material and interviews analysts who helped produce a U.S. intelligence report that found the Kremlin "aspired to help" Trump by discrediting Hillary Clinton.

That way, Warner said, when the committee interviews "some of these bigger names, we'll know what to ask them."

Manafort also faces scrutiny over his association in the mid- to late-2000s with a Russian industrialist who is close to President Vladimir Putin of Russia. Manafort consulted for Oleg Deripaska, and in 2008, created an investment partnership with $19 million from Deripaska.

In 2005, according to an AP report in March, Manafort pitched Deripaska an international public-affairs campaign that would bolster Putin-friendly governments in eastern Europe and weaken anti-Russian figures. "This model can greatly benefit the Putin Government," Manafort wrote, according to AP.

Manafort did not deny making the pitch but said he said he consulted only on Deripaska's "business and personal matters" and "did not work for the Russian government."

Deripaska denies being involved in any plan to influence politics that would benefit the Russian government, saying, "I have never made any commitments or contracts with the obligation or purpose to covertly promote or advance 'Putin's Government' interests anywhere in the world."

Manafort's history

For years, Manafort's firm made millions boosting the images of controversial foreign leaders such as Ferdinand Marcos of the Philippines while also advising the Republican presidential campaigns in the 1980s and 1990s.

Manafort lobbied locally for Trump in the 1980s and 1990s to help him develop casinos and residences. In 2006, Manafort and his wife Kathleen bought Apartment 43G in Trump Tower for $3.7 million.

By then, Manafort had largely disappeared from U.S. politics. In the mid-2000s he was called to Ukraine to help a struggling Party of Regions, which leans toward Russia. The party's candidate, Yanukovych, had lost the 2004 presidential election to a pro-Europe candidate and needed help.

The US embassy noted Manafort's arrival. In a 2006 cable, ambassador John Herbst said Yanukovych's political party was undertaking an "extreme makeover" from its history as "a haven for Donetsk-based mobsters and oligarchs."

"The effort enlists the help and advice of veteran K Street political tacticians," wrote Herbst, who served from 2003 to 2006. He added that an Internet news site said Manafort's firm had been hired "to do the nipping and tucking."

The cosmetic work, however, did not alter the Russia-leaning views of Yanukovych and his party, said ambassador William Taylor, who served from 2006 to 2009.

Yanukovych continued to take pro-Russia stands on divisive issues such as making Russia an official language of Ukraine, opposing free trade with Europe and cooperation with NATO, and favoring trade pacts with Russia.

"These are traditional Ukrainian battle lines," Taylor told CNN. "I don't know the degree to which Manafort emphasized them."

Taylor said Manafort visited him regularly in Kiev, Ukraine's capital.

"He was very transparent about his policy recommendations and political recommendations and style recommendations to Yanukovych," recalled Taylor, now the executive vice president of the U.S. Institute of Peace in Washington.

"He said he was trying to convince Yanukovych that a winning political strategy would be toward economic growth, deregulation, corporate governance and an investment climate. That would be a winning strategy not just with the West, but also, he said, in Ukraine."

Manafort continued to advise Yanukovych during his presidency, which came to an abrupt end in early 2014 when he fled the country during violent street protests that were triggered by his decision to scrap a European trade deal and pivot toward Russia. Yanukovych remains in exile in Russia.