DULUTH - Mayor Roger Reinert expressed worry this week about billionaire Kathy Cargill's extensive Park Point property purchases, assuring residents the city intends to explore its options.

"The plan for these properties is unknown, and that is concerning to many, including me," Reinert wrote in a social media post Tuesday.

He said the city is "investigating zoning and other regulations that would apply to future construction and also address future demolitions." Nine of the 12 homes purchased in recent months by Cargill's limited liability company, North Shore LS, have been torn down. City permits were issued Monday to cut utilities to prepare for demolition of the remaining three.

The LLC has spent $6.7 million acquiring the single-family homes, some in multiparcel sales, on the fragile sandbar in the last 14 months. More than 20 parcels now belong to the LLC. Many of the properties were sold at twice their estimated value or more. It's triggered anxiety from neighborhood residents and those who use the 7 miles of its iconic public beach.

Reinert told city councilors Monday that he had not heard back from Cargill after sending a letter last month asking her to meet with him and the Park Point Community Club. He asked council members to co-sign a new letter he is sending after Cargill's company closed on two more properties in late February.

At Monday night's City Council meeting, President Roz Randorf said she was concerned about the loss of so many homes.

Chief Administrative Officer David Montgomery assured councilors that every sale has been lawful, and the city will have input if rezoning or redevelopment requests are made.

Park Point is zoned for mixed use in some areas, but it's largely residential. All of Cargill's properties lie in residential zones, according to city maps.

In his social media post, which included a video in front of one of the torn-down properties, Reinert tried to reassure residents that the point's vast parkland will remain public, along with the beach and its street access points.

"Park Point is a unique Duluth neighborhood, and geographically a place like no other in the world," he said. "Public access to Lake Superior is not going anywhere."

Reinert, who took office in January, reminded homeowners on the point, where he also once lived, that they can choose not to sell their property.

Cargill has not returned repeated messages for comment, including one left Tuesday.

Park Point residents have a litany of worries, including the eventual effect on property taxes, the loss of badly needed single-family housing, and fear of irresponsible development of the fragile and historically significant sandbar, long beset by erosion.

Josie LaPorte serves on the city's Parks and Recreation Commission, and Park Point is in her district. She, too, sent a letter to Cargill that went unanswered.

She wants to ensure good stewardship of the delicate land, she said, to avoid further erosion, disruption of migration patterns and removal of green space.

"And the fact that we're seeing someone who's making a major investment in this community come in and tear single-family homes down can be seen as kind of a punch in the face to people who already live here," LaPorte said.

Randorf on Tuesday said she'd like more information about Cargill's plans to allay residents' fears.

"And I represent her as her City Council person on the point and I would love to have a relationship," she said.

Cargill is married to James Cargill II, one of a dozen heirs to Cargill Inc., the Minnetonka-based global food and agribusiness giant and the largest privately held company in the nation.