The teenage girl fancied herself an archaeologist. When she saw bones exposed in a road project in the Twin Cities, she picked them up and gave them a coat of varnish. Then they gathered dust in a box for decades.

She was an old woman when, fretting that she'd done something awful and frightened about being prosecuted, she asked an intermediary to contact the state. The bones she had tried to protect had become a guilty burden.

"She just wanted to give them back. She said, 'I'm sorry,'" recalled Jim Jones, cultural resource director for the Minnesota Indian Affairs Council. "We just said, 'Thank you, we're going to take care of them.'" And the bones were reburied.

Those remains probably came from one of the thousands of Indian burial mounds that dot the Twin Cities area. More than 12,500 mounds are scattered across Minnesota. They are especially common in places like Bloomington, Eden Prairie, Red Wing and around Lake Minnetonka, where Mound -- formerly known as Mound City -- was named for the bumps and rises that marked Indian burial sites.

In Minnesota, it's a felony to "willfully disturb" a burial ground. Trouble is, Dakota and later Ojibwe Indians who lived here honored their dead by burying them in the best locations they could find: high, dry spots that often offered beautiful views of lakes and rivers -- the same spots coveted by today's developers.

On Bartlett Boulevard in Mound, houses were built over the last century along the Lake Minnetonka shoreline, where in the 1880s there were at least a dozen burial mounds.

Donald Biorn has a mound in his front yard, and it has bugged him since he moved in 32 years ago. The top of the 6-foot-tall rise was pitted with holes when he bought his house, and he believes "treasure hunters" already removed whatever was there.

"I can't move my garage, I can't build onto the house," he said. "I never tried, so it's not my problem. But it would be a problem for people who buy this house."

One of Biorn's neighbors is in court over mounds on his land. When he tried to expand his garage, he discovered it is built into the side of a burial mound. He had to abandon his plans and has sued a title company over his purchase of the property in 2005. He declined an interview while the matter is in court.

State Archaeologist Scott Anfinson said that while lawsuits are not common, clashes between development and burial sites consume virtually all of his time. It's his job to authenticate unplatted burial grounds more than 50 years old, then set buffer zones around them. He juggles 20 live cases at a time, many of them around Red Wing and Lake Minnetonka.

"A big part of my job is disappointing people," Anfinson said. "If you have graves on your property, you are done."

If a gravesite is Indian, Anfinson turns the issue over to Jones and the Indian Affairs Council, as required by state law. Jones makes a recommendation to the relevant tribal council for a final decision. Intact burial mounds are not moved or altered.

But up until the 1970s, people did what they wanted with the mounds. In the early 1900s, tourists visiting resorts and hotels near Mound "came out with pickaxes and just dug for sport," said Mound City Manager Kandis Hanson. The Wayzata public library was built on a mound site in the 1930s. Science digs of Minnesota mounds didn't end until 1974.

In 1978, when Anfinson was a highway archaeologist, Indian burials were uncovered during excavation for fill dirt near construction of the new Hwy. 77 bridge over the Minnesota River. The private landowner who was selling the fill dirt refused to stop the excavation, Anfinson said. He and a colleague hurriedly removed the remains of apparently Christianized Indians who had been buried in coffins as well as an older interment of what appeared to be a medicine man. The bodies were reburied on Lower Sioux Community land.

Such digging and construction have taken a toll on the burial sites. In the 1880s around Lake Minnetonka, 524 mounds were mapped at 48 sites. Today, about 40 mounds remain at 12 sites near the lake.

But not all mounds look like the stereotypical bump in the ground. Some were never more than a foot or two high, and others have been flattened by plowing and other activity, Anfinson said. If burial pits remain underground, the site is still considered a graveyard.

It's those invisible remains that create controversy -- like an incident at Bloomington Central Station, where construction was halted in 2004 after bulldozers uncovered bones. The remains of 55 people were found on the site. Indian activists protested, but eventually an agreement was worked out to re-inter the remains nearby and the project continued.

Feelings from that incident remain raw, and Bloomington and other cities are trying to ensure it does not happen again. Now, more than 250 mounds in 16 groups along Bloomington's Minnesota River bluffs are marked on planning documents, Senior Planner Bob Sharlin said. The city has a mound preservation plan, and some mounds are fenced off. The city also investigates any reports of people digging in the area, and when land deeds are registered, the presence of mounds is noted.

Development along Eden Prairie's bluffs, where mounds also are located, is limited by city ordinance. Buffer zones have been established, as state law requires, and developers are warned not to disturb the graves. "Most people are respectful," said John Gertz, who until May was the city's historic preservation planner.

In Mound, a church redesigned an addition when construction unearthed bones on one side of the site. The city's building permit application included a warning that property owners were responsible for checking the city's comprehensive plan to see if Indian remains were on their land.

Jones said that disturbed sites are the hardest to deal with. He makes recommendations to tribal councils on whether a site should be protected or whether remains should be relocated.

He said he has encountered heavy equipment operators who are even worried they'll be haunted by the people they have unwittingly dug up. Most people want to do the right thing, Jones said.

Like Jerry Smith of the Lion's Club in Ottertail, Minn. Last week he learned that it couldn't move a giant metal statue of an otter to a wooded hill at a prominent intersection near town, because the hill is one in a string of mounds.

"We'll look for another site," Smith said. "We don't walk on people's graves. That's just showing respect for the dead. I would expect the same if I was Native American."

Jones said that in some places, Minnesota Indians traveled long distances year after year to bury relatives in the same mounds. He said those places deserve to be undisturbed.

"It's the respect we have for loved ones, no matter how long they've been gone," he said. "Even if evidence of a mound is gone ... people need to understand that this is a sacred place. This site was chosen for a reason.

"It is instilled in us. You respect your loved ones."

Mary Jane Smetanka • 612-673-7380