The rural region is emerging as one of the top oil producing areas of North America. Officials say up to 30,000 more workers could descend on the Bakken oil fields of Montana, North Dakota and Saskatchewan in the next few years.

The recent kidnapping and brutal murder of Montana teacher Sherry Arnold tragically underscored the changes brought on by the rapid pace of drilling. Two men are in custody, but the case has left residents shaken and led to a huge rise in applications to carry concealed weapons in Montana and North Dakota.

In the wake of Arnold’s killing in the town of Sidney, which is quickly being overtaken by the boom, federal prosecutors began a two-day retreat Monday for about 150 police, sheriffs, federal agents and other law enforcement to craft a common strategy to deal with rising crime.

Towns like Plentywood, population 1,600, were until recently places “you could send your kids to the pool in the summertime on their bikes and not have to worry about it,” said Sheridan County Attorney Steven Howard.

“All those things are changing,” he said, adding that the Arnold case “has had a chilling effect on our people.”

Monday’s conference already was being planned before Arnold’s death, said Michael Cotter, the U.S. attorney for Montana. But Cotter said the killing illustrated the importance of close coordination among law enforcement as officials gird for more crime.

Government officials predict the boom could last another decade or more as companies tap into a reserve estimated by the U.S. Geological Survey to hold more than 4 billion barrels of crude. Oil company executives say there’s even more, upwards of 20 billion barrels that will be extracted using drilling techniques that were only recently perfected.

Towns like Dickinson already have seen the negative spinoff effects from workers hoping to cash in on the boom. For many agricultural communities, including Plentywood, officials say the changes have just begun.

The situation is exacerbated by a housing shortage that is spurring the construction of sprawling “man camps” that can accommodate hundreds of out-of-state oil workers.

“The population flux will naturally bring increased criminal activity to the area. It is imperative that our law enforcement establish open lines of communication between each other,” Cotter said.

The suspects in Arnold’s killing — 48-year-old Lester Van Water and 22-year-old Michael Spell — allegedly traveled to the Bakken from Colorado in search of jobs in the oil patch. Court records suggest Spell and Waters had been smoking crack cocaine and were living out of Waters’ vehicle when they snatched Arnold off a Sidney street in the pre-dawn hours of Jan. 7.

Industry representatives say companies go to lengths to ensure the workers they hire won’t cause trouble — either on the job or in the community.

Drug tests and background checks are standard for many companies, said Kari Cutting with North Dakota Petroleum Council. She added the lack of housing can quickly deter would-be workers who show up without a position already secured.

Cutting noted that neither Spell nor Waters was employed by the oil industry, and the two had been in the region only a short time before the alleged crime.

“We do know there are challenges,” she said. “Any opportunity has challenges that need to be overcome, and we want to be part of the solution in all this.”

Some law enforcement officials, including Valley County Sheriff Glen Meier, said the increase in crime has roughly tracked the increase in population, meaning the actual rate of offenses has been little changed.

“You have to put it into perspective,” Meier said. “Ninety-nine percent of the people (working the oil fields) will be an asset to the community.”

Yet there are indications that communities and several Indian reservations in the Northern Plains have found themselves dealing with new types of crime more commonly associated with urban areas. Organized drug trafficking and prostitution rings top the list, officials said.

Mercer Armstrong with the Royal Canadian Mounted Police said the areas of southern Canada within the Bakken have seen a “major influx of criminality.” That includes organized criminal enterprises from British Columbia moving into rural areas to establish the drug trade, he said.

In the U.S., federal agencies including the FBI and Bureau of Alcohol, Tobacco, Firearms and Explosives are addressing the problem by adding new agents and working harder to share intelligence with state and local officials.

Montana and North Dakota also have more state troopers on the road, in part to address rising numbers of traffic offenses including driving while intoxicated.

Some law enforcement agencies are running into trouble as they seek to fill vacant posts. Qualified applicants will pass over deputy positions that start at less than $20 an hour to take oil field jobs that can pay two to three times as much.

The result, said Tim Purdon, the U.S. attorney for North Dakota, is that police are in “100 percent reactive mode, running from call to call.”

“Local departments have been squeezed to the point where they’re having trouble performing proactive police works. We don’t have the time,” he said.

The AP’s analysis showed coal exports to South Korea leapt 81 percent last year to more than 10 million tons. India saw a 65 percent jump, to 4.5 million tons. And Japan bought almost 7 million tons — a 119 percent increase — as the nation sought alternatives to nuclear power after an earthquake and tsunami prompted the Fukushima nuclear complex meltdown.

King Coal faces a tougher outlook in the U.S., where competition from cheap natural gas and costly new rules for power plants are eroding its historic dominance in electricity generation.

Coal’s share of the domestic power supply has dipped by more than 20 percent in the past several years, forcing companies to search out new customers overseas or risk having to cut production from U.S. mines that produced almost 1.1 billion tons last year.

“There’s no question that our supplies of coal are adequate. The question is, how do we find new markets for coal to keep the share of electricity generation strong?” said Luke Popovich with the National Mining Association. “While its use is relatively declining here, it is absolutely soaring in most other places.”

Exports also are up to Brazil, China and several European nations seeking high-quality coal for steelmaking, according to the Energy Department data.

The Energy Department forecasts exports to drop slightly over the next two years, to about 99 million tons a year.

Companies including Arch Coal Inc. have offered more optimistic scenarios under which exports continue to grow. Arch has predicted export capacity could reach 245 million tons by 2015.

To make that happen, companies want new or expanded coal ports on the West and Gulf coasts. Pending proposals in Washington state would add tens of millions of tons of port capacity in coming years for coal that would be mined from the Powder River Basin of Montana and Wyoming.

Port expansions also are envisioned along the East Coast and in Texas, where Kinder Morgan Energy Partners plans to invest $140 million to expand a coal terminal in Houston. But many of those port plans are being challenged by the coal’s industry’s long-time opponents.

Environmentalists who filed dozens of lawsuits over the last decade to block new coal plants in the U.S. have turned new attention to export proposals in recent months. They fear any reduction in pollution from reduced domestic coal use will be cancelled out if the fuel is simply burned elsewhere.

The industry faces another challenge from coal-producing countries such as Australia, which has tapped into the new demand from Asia.

Over the last two years, flooding and other problems hampered Australia’s coal exports and provided an opening for U.S. companies. As Australia works past those problems, it’s uncertain how much room will be left for American competitors.

“High demand by China has rippled through the markets. It’s really an issue of how long this demand is going to last,” said Bill Watson, an analyst with the Energy Information Administration. “The prices have been very high, so anybody who can mine and ship coal certainly has a lot of incentive to do that.”