Spending reports that were filed with the FEC Sunday reveal this sharp uptick, which accounted for more than 25% of the campaign's total spending that period, the NYT reports. The campaign and its two joint committees have spent $2.1 million on legal fees this year.

Why it matters: That coincides with the Russian interference probes' escalation, and is nearly twice as much as the campaign spent the three months before.

The fees: The largest chunk of that, $830,000, went to Jones Day, the law firm charged with representing the campaign in connection with the Russia investigations, campaign finance law, and litigation stemming from the election. $238,000 went in July and August to the lawyer representing Donald Trump Jr., Alan Futerfas.

The largest chunk of that, $830,000, went to Jones Day, the law firm charged with representing the campaign in connection with the Russia investigations, campaign finance law, and litigation stemming from the election. $238,000 went in July and August to the lawyer representing Donald Trump Jr., Alan Futerfas. The latest: Reince Priebus interviewed with Special Counsel Bob Mueller's investigation Friday.

Go deeper: All the Trump associates who have testified before Congress