The Maine Department of the Secretary of State expressed concern last fall over a “lack of progress and cooperation” from UPS as officials investigated how 250 ballots were found in a Newburgh woman’s Amazon package.

In an email to staff at the parcel delivery service in October, Kate McBrien, chief deputy and chief of staff to the secretary of state, said the office was not comfortable using UPS for shipping going forward.

“Secretary (of State Shenna) Bellows remains concerned about the lack of progress and cooperation from UPS headquarters regarding what happened in the absentee ballot delivery with ballots in the custody of UPS appearing outside the chain of custody,” McBrien wrote.

The email is among several dozen pages of correspondence involving Bellows and staff that the Press Herald obtained through a Freedom of Access Act request.

The emails shed new light on the ongoing investigation into the misplaced ballots and state officials’ frustration with UPS.

A spokesperson for UPS said Wednesday that the company has fully cooperated with the state and shared the results of its own internal investigation into the misplaced ballots.

“This was due to an unintentional error on the part of our package handlers,” the spokesperson said in a statement. “The box containing the ballots was damaged and the contents were inadvertently repackaged in a different shipment. We have taken corrective actions both operationally and with the employee involved to help prevent this from happening in the future.”

The 250 misplaced ballots were discovered at the end of September by a woman in Newburgh who turned them into the town office. Ellsworth officials said at the time that a recent shipment of absentee ballots was missing the same number of ballots.

Bellows said at the time that her office would switch ballot delivery couriers following the mix up. They decided to use a different carrier, Vital Delivery, for the last part of the delivery process, according to the emails.

The secretary of state’s office told UPS on Oct. 10 that it did not want the drivers involved in deliveries to Ellsworth and Newburgh to deliver any more ballots for the upcoming November election, the emails obtained by the Press Herald said.

UPS responded that it could not guarantee that those two drivers would not be involved “due to operational constraints.”

McBrien replied noting Bellows’ concerns. “She is equally concerned that a package of absentee ballot envelopes was reboxed, relabeled and mailed to a third party with which neither the printer nor the State of Maine has any relationship,” McBrien wrote.

“Our office remains hopeful that we can work with UPS again for the next election cycle, but that will be dependent on getting answers — wherever they may lead — in the current investigation, so we can ensure that it never happens again,” she added.

It’s unclear if UPS responded to that email, which was sent late in the day on the final day covered in the Press Herald’s records request.

A spokesperson for the secretary of state’s office referred questions to the Office of the Maine Attorney General, which is leading the current investigation into the misplaced ballots. A spokesperson for the office declined to comment, citing the ongoing probe.

The incident prompted calls for stronger election security as Maine was preparing to vote on Question 1, a referendum that would have required voters to show photo identification and would have placed new restrictions on absentee voting. The measure was soundly defeated 64% to 36%.

Bellows, a Democrat who is running for governor, has said Maine elections are secure, and suggested at the time that “bad actors” may have tampered with the ballots.

This story was updated Wednesday to add comment from UPS.