WASHINGTON ― President Donald Trump probably doesn’t need another reason to be upset over the special counsel investigation into Russian interference in the 2016 election, which has already swept up at least three members of his campaign. Here’s one anyway: Prosecutors working for Robert Mueller say a Trump Tower condo owned by Trump’s former campaign manager, Paul Manafort, isn’t worth nearly as much as Manafort claims.

In a court filing on Saturday, Manafort offered up a Trump Tower condo with an “approximate net asset value” of $3 million as collateral in a $12 million bail package he proposes to get himself off house arrest as he awaits trial.

But Mueller’s team thinks Manafort’s numbers are off. Prosecutors say the defense team is greatly overestimating the value of a condo in the Manhattan building named after the president, and aren’t even sure Manafort has any equity in his Trump Tower property.

Manafort’s lawyers reportedly told prosecutors that the $3 million net asset value was “based on a fair market value of $6 million, reduced by a $3 million mortgage on the property.” But that $6 million estimate isn’t backed by an appraisal, or even by “open source estimates” that Mueller’s team could find.

“Manafort provided the government with an open source estimate for a different unit in the building, listed as approximately $4.5 million, which Manafort believes is below the fair market value of his own unit, which is on a higher floor,” prosecutors wrote. “Meanwhile, the government has searched open source real estate value estimators and found one that lists the value of Manafort’s own unit as $2.5 million, and another that lists the value as $2.7 million.”

Drew Angerer via Getty Images

Manafort, who surrendered to the FBI on Monday on a 12-count indictment that potentially exposes him to decades in prison, is due to appear before a federal judge on Monday to work out conditions for his release. U.S. District Judge Amy Berman Jackson indicated in court last week that she’ll consider allowing Manafort to leave his home, but seemed hesitant to remove his electronic monitoring because she believes he’s a flight risk.

With the value of Manafort’s Trump Tower unit under dispute, the court filings suggest that federal prosecutors and the former Trump campaign manager’s attorneys may spend part of Monday’s hearing arguing over the value of a condo in the building, where the president also maintains a home.

Manafort bought the Trump Tower unit for more than $3.6 million back in 2006 through a limited-liability company called John Hannah, which according to NBC News combined his middle name with the middle name of his former business partner Rick Davis. The deed was transferred to Paul Manafort and his wife in 2015, and the couple took out a $3 million mortgage on the property. If the condo is now worth only $2.5 million, it may mean Manafort is underwater, meaning he owes more on the property than it’s worth.

Without an independent appraisal, prosecutors said they can’t agree the property can be used as part of Manafort’s bail package.

Kevin Lamarque / Reuters

HuffPost asked a spokesman for the special counsel whether prosecutors believed the value of Manafort’s Trump Tower condo had dropped in recent years due to the president’s polarizing influence. The spokesman declined to comment, or to elaborate on the “open source real estate value estimators” they consulted. Zillow, one such estimator, values Manafort’s condo at $2.5 million ― matching a figure prosecutors used in their response to Manafort’s bail proposal.

The value of properties in Trump Tower appears to have declined since Trump’s election. In October 2016, The New York Times spoke with a broker of a Trump Tower apartment listed for $2.195 million, which at the time had been on the market for more than nine months. More than a year later, the property was listed at $1.9 million. Another Trump Tower condo reportedly listed for $2.99 million ultimately sold this year for $1.9 million. Earlier this year, Town & Country ran a story headlined, “Nobody Is Buying Apartments In Trump Tower,” which said there were a “staggering” number of units available in the building.

One real estate agent who researched the value of Manafort’s property told HuffPost there was “no way” the unit was worth as much as Manafort’s lawyers claimed. At most, the value might be around $3.8 million, roughly what Manafort paid for it back in 2006. “I have trouble believing an appraiser would value the property anywhere close to $6 million,” the agent said.

CORRECTION: A previous version of this story stated incorrectly that Rick Davis is Manafort’s co-defendant. Davis is his former business partner; his co-defendant is Rick Gates.

