BANGOR, Maine — Attorneys for the company that owned the shuttered Bucksport paper mill and the industrial salvage firm that is buying it denied Tuesday in federal court there was a buyer that wanted to purchase the property and continue making paper.

U.S. District Court Judge John Woodcock said it was going to be difficult for him to decide whether the sale violated antitrust laws when he had no evidence a competitor existed — just “a suggestion there were people who were interested” in the property.

Gov. Paul LePage said in a press release issued Thursday that “one firm had expressed genuine interest in acquiring the asset in Bucksport to continue papermaking activities.”

Kimberly Ervin Tucker, a Lincolnville attorney for the union that filed the lawsuit, told Woodcock that confidentiality agreements among Verso Paper LLC and potential buyers prevented her from learning the name of that firm.

The judge said he would issue a ruling early next week on a motion seeking to block the sale of the mill, owned by Verso, to AIM Development for $58 million.

The International Association of Machinists sued Verso last month in an effort to halt the pending sale of the mill to a subsidiary of scrap dealer American Iron and Metal. The lawsuit alleged the sale violates federal antitrust laws and is part of an attempt to monopolize the market for coated paper, which is used in magazines and catalogs.

The union also accused the company of trying to “evade its legal obligation” under state law to make timely payments for severance, final wages and accrued 2015 vacation time. Woodcock a week ago dismissed that portion of the lawsuit in an 86-page ruling.

Dave E. Barry, who represents Verso, and Clifford Ruprecht, who represents AIM, told Woodcock the sale of the mill and power plant does not violate antitrust laws.

Ruprecht said AIM is “ready, willing and able to sell the mill to someone willing to pay more than the sale price, but we’ve seen no evidence that such a buyer exists.”

Union attorney Donald Baker of Washington, D.C., said the U.S. Justice Department was wrong to allow Verso to acquire rival coated paper maker NewPage for $1.4 billion last week. Despite claims to the contrary from millworkers and unions, antitrust regulators determined the closure of the Bucksport mill was unrelated to the proposed combination of the two firms.

“I disagree with the Department of Justice,” Baker told Woodcock. “The purchase of NewPage is related to the sale of the Bucksport mill. You can call it an inference [instead of evidence] but the merger was not going forward with the Bucksport mill.”

To halt the sale, even temporarily, Woodcock would need to find that Verso sold the Bucksport mill to AIM so the Justice Department would approve the NewPage merger and make sure the mill did not become a competitor in the papermaking market.

The closing on the sale to AIM — tentatively scheduled for Friday — has been delayed because of the lawsuit and because the Federal Energy Regulatory Commission has not yet agreed to transfer permits to operate the power plant to AIM, Verso’s attorney told Woodcock. As soon as FERC issues its approval, the closing will be held, Barry said.

LePage has intervened in that process, asking the regulators not to give expedited review to the transfer of power assets at the mill to AIM and “carefully assess” whether the plan could cause any reliability issues. The governor also has asked state regulators to give close scrutiny to the transfer of renewable energy credits to the new owner.

In filings with the Public Utilities Commission this week, an attorney for Verso wrote operations at the biomass plant will be in line with past use, mostly operating on biomass purchased from outside sources.

In testimony filed with the court, Jeff McGlin, AIM’s U.S. vice president for development, wrote that AIM has hired an outside contractor to run the power assets and already has made payments to them in preparation of taking over their operation.

BDN writers Darren Fishell and Bill Trotter contributed to this report.