By the time four former Blackwater security guards were sentenced this week to long prison terms for the 2007 fatal shooting of 14 civilians in Iraq, the man who sent the contractors there had long since moved on from the country and the company he made notorious.

Erik Prince, the founder of Blackwater, a former Navy SEAL and heir to a Michigan auto parts fortune, has spent the last few years searching for new missions, new fields of fire and new customers.

He has worked in Abu Dhabi, United Arab Emirates, and now focuses his efforts on Africa, with ties to the Chinese government, which is eager for access to some of the continent’s natural resources. Prince’s current firm, Frontier Services Group, provides what it describes as “expeditionary logistics” for mining, oil and natural gas operations in Africa, and has the backing of Citic Group, a large state-owned Chinese investment company.

The private security industry that Prince helped bring to worldwide attention has fallen from public view since the height of the wars in Iraq and Afghanistan. But the two conflicts sped the maturation of security firms from bit players on the fringes of global conflicts to sprawling multinational companies that guard oil fields in Libya, analyze intelligence for U.S. forces in Afghanistan, help fight insurgents in parts of Africa and train U.S.-backed militaries in Iraq, Afghanistan and elsewhere.

“This industry is now truly global,” said Sean McFate, author of “The Modern Mercenary,” a book on the private security industry. “That’s the legacy of Blackwater — they didn’t really make the business, but they’ve symbolized it. They’ve become the hood ornaments for an industry that was for centuries pretty much illegal, and now it’s pretty much re-emerged.”

Security companies say they have taken steps toward ensuring that their guards are well trained and behave professionally. Industry officials say that one of the consequences of the 2007 shooting has been to impose more rigorous controls on contractors handling diplomatic security for the State Department, as Blackwater was doing when its security guards fired into Baghdad’s crowded Nisoor Square, killing unarmed Iraqis, enraging the country.

“Those sort of reckless days with contractors running around like cowboys are over,” said one senior industry executive, speaking only on condition of anonymity. “It is 180 degrees different. There is a lot more oversight and regulation.”

Others, including Ryan Crocker, the former U.S. ambassador to Iraq, agree that there are more controls over contractors. Still, there are calls for greater transparency.

Just tracking the growth of the industry as it has expanded beyond work for the U.S. government has proved exceptionally difficult. In Africa and the Middle East, most governments do not publicize the companies they hire, and private businesses are similarly tight-lipped. As a result, there are no solid numbers on how many armed contractors are currently working around the world, and estimates of industry revenues range from a few billion dollars to $100 billion.

Even determining how many private security contractors are employed by the U.S. government is nearly impossible because the contracts are often opaque, subcontractors do much of the work on the ground and some of the business is classified. State Department officials refused on Tuesday to provide statistics on how many contractors it uses today.

The U.S. Central Command, which is in charge of military forces in the Middle East, Afghanistan and Pakistan, reported in January that 54,700 private contractors worked for the Defense Department in its areas of responsibility.

In Afghanistan alone, where about 9,800 U.S. troops are deployed, the Pentagon is paying for almost 40,000 private contractors, more than a third of whom are American, according to the CENTCOM report. Only a few hundred, though, are involved directly in security, with others doing everything from serving food to intelligence work.

Last year, the United States also sought to hire private military contractors in Iraq to buttress the small number of U.S. troops there to help stop the advance of the Islamic State. The contractors’ tasks would involve assisting the Iraqi military, including administrative tasks, public affairs and operational planning, according to the Pentagon.

Experts believe that private security contractors are likely to remain a permanent part of the U.S. presence overseas. “You are going to keep having contractors for security,” said Crocker, the former ambassador. “You can’t do things in Iraq or Afghanistan without them. You just can’t.”

Ann Hagedorn, the author of “The Invisible Soldiers,” a 2014 book about security contractors, agreed that contractors will have plenty of work.

“Iraq has been called the first contractors’ war,” she said. “With an increasing dependence on these companies worldwide, we could easily be going into another contingency operation that will be another contractors’ war.”

Blackwater, the company Prince built into a corporate symbol of the U.S. war in Iraq, never really recovered from the Nisoor Square shootings and its many other controversies and legal woes. In addition to the prosecution of the guards in the 2007 shooting, five top Blackwater executives were indicted on weapons-related charges, the company was forced to pay millions of dollars in fines to the State Department for export law violations, and it faced costly civil lawsuits from the families of the victims of Nisoor Square and the families of four guards killed in Fallujah, Iraq, in 2004.

Blackwater was eventually blocked from providing diplomatic security in Iraq. Meanwhile, Afghanistan banned private security companies in 2012 after years of allegations of guards killing civilians and other abuses. Foreign military and diplomatic missions were exempted, however.

In response to the controversies surrounding Blackwater, Prince first renamed the company and then sold it in 2010. Now known as Academi, it has since been resold and merged, along with one of its main competitors, Triple Canopy, into the Constellis Group. The consolidated company is still a major player in security contracting for the U.S. government and other customers, while Blackwater’s sprawling facility in Moyock, N.C., is now one of Academi’s major assets as a training center.

Prince emerged from the wreckage of Blackwater relatively unscathed, never facing any criminal charges from the multiple government investigations into the company. But he was embittered by the legal scrutiny and negative publicity, all part of what he believed were unfair political attacks on him and his firm. He moved his family to Abu Dhabi in 2010, when one former colleague told The New York Times that Prince “needs a break from America.”

In his 2013 memoir, “Civilian Warriors,” Prince defended the actions of Blackwater as well as the guards who fired in Nisoor Square, protesting that “shifting political tectonic plates crushed my company as an act of partisan theatrics.”

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