A series of letters sent back and forth between State Department officials and Hillary Clinton's legal team last year sheds light on the agency's scramble to recover classified documents that had been stored in unsecured environments.

The letters, made public Wednesday by conservative watchdog Judicial Watch, suggest the State Department was concerned about Clinton's lawyers handling records that had been upgraded to "secret," the second-highest level of classification in government.

Recovering now-classified emails that have been potentially touched by dozens of unqualified people posed problems for the State Department, especially since Clinton's lawyers said they were unable to delete the sensitive records as requested because they faced preservation orders from the House Select Committee on Benghazi.

Patrick Kennedy, State's undersecretary for management and the agency's top record-keeping official, warned Clinton's attorney, David Kendall, in May of last year that an email discussing Benghazi had been upgraded to "secret" and should be deleted from the Clinton's records.

Kendall promised in a subsequent letter to send hard copies of the email to the State Department, but argued Clinton could not delete the "secret" email because she faced separate orders from the Benghazi committee, the State Department inspector general and the intelligence community inspector general.

"I therefore do not believe it would be prudent to delete, as you request, the above-referenced email," Kendall wrote to Kennedy in June.

Contents of some of the letters were first made public in September, when scrutiny of Clinton's private email use had begun to peak ahead of her highly anticipated appearance before the Benghazi committee the following month.

In August, the FBI had confiscated Clinton's server after the two inspectors general who had issued preservation orders discovered emails classified up to "top secret" among the former secretary of state's records.

But the letters hold new significance in light of the news late last month that the State Department had upgraded 22 emails to "top secret," ending the dispute between the intelligence community and State over the highly sensitive nature of those records.

For example, one letter from Kennedy to Clinton's legal team in June laid out a list of 25 emails that had been classified up to that date. Since then, more than 1,600 emails have been upgraded to classified.

Kennedy described each email in detail and outlined specific instructions for the identification and removal of each one, a process that would be difficult and time-consuming if Clinton and her team still had possession of all 55,000 pages of emails.