The Department of Justice could bring criminal charges in connection with a 2016 building collapse that resulted in the death of a worker, according to court documents obtained Monday by the Argus Leader.

The U.S. Attorney’s criminal investigation into Hultgren Construction is the second federal probe of the Copper Lounge collapse. The Occupational Safety and Health Administration launched an immediate civil investigation into the downtown Sioux Falls disaster in December of 2016.

News of the criminal investigation comes just two weeks after the city of Sioux Falls entered into a $50 million deal with Legacy Developments to build a hotel and parking ramp known as Village on the River.

Aaron Hultgren, the president of Hultgren Construction, is the director of operations and development for Legacy Developments and a personal guarantor for the Village on the River project.

Hultgren Construction was converting the former Copper Lounge bar into a drug store when the building collapsed Dec. 2, 2016. The collapse killed Hultgren employee Ethan McMahon and left a woman who lived in an upstairs apartment trapped under rubble for hours. Legacy Developments was the developer on the project.

Hultgren declined to comment Monday.

MORE: Copper Lounge building collapse: an oral history

The U.S. Attorney’s criminal investigation includes a review of more than 150 gigabytes of data related to McMahon’s death, “including video, photographs, interview statements, training materials, engineering plans, building permits, and email correspondence,” according to a court report filed in the name of Patrick B. Augustine, the secretary for the Department of Labor, which oversees OSHA.

“The secretary anticipates that the criminal investigation will continue for at least the next 90 days as the U.S. Attorney’s Office organizes and analyzes information related to the Dec. 2016 fatality,” wrote Jennifer Casey, a senior trial attorney for the department. “Given both the sensitivity and nature of the ongoing criminal investigation, the U.S. Attorney’s Office is unable to place a precise timetable on when its investigation will be concluded.”

Casey’s report, which was filed with a judge overseeing OSHA’s civil proceeding, was dated Nov. 20.

U.S. Attorney Randy Seiler said he could not comment on the investigation.

An OSHA investigation into the collapse resulted in more than $200,000 in fines assessed against Hultgren Construction for nearly two dozen worker safety violations, including two that were “willful.” The violations are the most serious that can be assessed by OSHA. Hultgren Construction appealed those fines, and it’s that appeal which has been postponed because of the criminal investigation.

Scott Allen, an OSHA spokesman, said that because the case is considered open, OSHA is unable to comment.

OSHA investigations resulting in criminal investigations are rare. In 2013, OSHA made 39,228 inspections but referred just three cases for criminal prosecution.

Minnehaha County State's Attorney Aaron McGowan said in the days following the collapse that construction mishaps only result in criminal charges when the offense rises beyond negligence to reckless behavior.

Some city councilors raised the collapse as a concern when they were asked earlier this month to approve the Village on the River deal. The 13-story project which includes a 120-room hotel, commercial space and a 525-space parking ramp, will be built adjacent to where the Copper Lounge once sat.

The City Council approved the project, which includes $21.3 million in taxpayer money, on Dec. 5. The approval becomes legally binding on Dec. 29.

Councilor Theresa Stehly, the most vocal critic of the mixed-use parking ramp project, for months criticized the deal in part due to Legacy Developments and Hultgren's involvement in the building collapse.

She said Monday after learning about the federal criminal investigation that she intends to ask the City Council to stop the project until the investigation is complete.

"I certainly have compassion for this man, but at the end of the day, we don’t want to build a structure on shaky ground, fiscally or physically," she said. "Our citizens deserve to have this looked into and I'll do my best."

Councilor Greg Neitzert said prior to voting in favor of the partnership with Legacy Developments and the contract guarantors, he inquired with the city attorney's office about what ramifications, if any, the building collapse could have on this project. He was assured it wouldn't.

"I received assurances that we are protected by any eventualities by the terms in the partnership agreement. I trust that and am confident in that," he said. "But you'd have to be out of your mind not to concede the optics are awful."

Officials with Mayor Mike Huether's administration, who supported the Village on the River project, would not comment citing the ongoing investigation.