“The incident rate for Blackwater is higher, there is a distinction,” said a senior American government official who insisted on anonymity in order to discuss a delicate, continuing investigation. “The real question that is open for discussion is why.”

Image Erik Prince, the founder of Blackwater USA, in June at a panel discussion on security issues in Cary, N.C. Credit... Sara D. Davis/Associated Press

A Blackwater spokeswoman declined to comment.

Blackwater, based in North Carolina, has gained a reputation among Iraqis and even among American military personnel serving in Iraq as a company that flaunts an aggressive, quick-draw image that leads its security personnel to take excessively violent actions to protect the people they are paid to guard. After the latest shooting, the Iraqi government demanded that the company be banned from operating in the country.

“You can find any number of people, particularly in uniform, who will tell you that they do see Blackwater as a company that promotes a much more aggressive response to things than other main contractors do,” a senior American official said.

Today, Blackwater operates in the most violent parts of Iraq and guards the most prominent American diplomats, which some American government officials say explains why it is involved in more shootings than its competitors. The shootings included in the reports include all cases in which weapons are fired, including those meant as warning shots. Others add that Blackwater’s aggressive posture in guarding diplomats reflects the wishes of its client, the State Department’s Bureau of Diplomatic Security.

Still, other government officials say that Blackwater’s corporate culture seems to encourage excessive behavior. “Is it the operating environment or something specific about Blackwater?” asked one government official. “My best guess is that it is both.”

Blackwater was founded in 1997 by Erik Prince, a former member of the Navy Seals, and is privately owned. Most of its nearly 1,000 people in Iraq are independent contractors, rather than employees of the company, according to a spokeswoman, Anne Tyrrell. Blackwater has a total of about 550 full-time employees, the she said.

Its diplomatic security contract with the State Department is now the company’s largest, Ms. Tyrrell said, while declining to provide the dollar amount. The company also provides security for the State Department in Afghanistan, where it also has counternarcotics-related contracts.