By Jonathan Beale
BBC News, Washington
Questions about one private security firm's actions have put a whole industry on trial.
As many as 20,000 private security contractors are working in Iraq
The firm in the dock is Blackwater; the industry under the spotlight is that of private security contractors.
Blackwater is a well-established private security firm that has its headquarters in North Carolina.
But it is Blackwater's actions in Iraq that have sparked the debate - to be precise, what happened in a Baghdad square on 16 September that left 11 Iraqis dead.
The sequence of events is in dispute. Iraqis say that the Blackwater guards, who were protecting an American diplomatic convoy, opened fire on innocent civilians.
Blackwater and the US state department say that the convoy came under attack.
The incident is now under investigation by both the Iraqi and US governments. The FBI has also sent out a team to Baghdad to find out whether Blackwater was involved in criminal actions.
First to fire
Blackwater has also come under the scrutiny of the US Congress.
On Tuesday, the firm's head Erik Prince, who normally shuns the limelight, was giving evidence to the House Committee on Oversight and Government Reform.
BLACKWATER USA FACTS
Founded in 1997 by former US Navy Seal Erik Prince
Headquarters in North Carolina
One of at least 28 private security companies in Iraq
Employs 744 US citizens, 231 third-country nationals, and 12 Iraqis to protect US state department in Iraq
Provided protection for former CPA head Paul Bremer
Four employees killed by mob in Falluja in March 2004
The Democratic staff of the committee had already released some damning allegations gleaned from Blackwater and US state department internal emails.
Their report says that Blackwater has been involved in 195 shooting incidents in Iraq since 2005 and in more than 80% of those cases Blackwater guards were the first to open fire.
The committee report also criticises the state department's oversight, saying that it was more interested in getting the company to pay off victims' families than actually investigating what really happened.
The state department was also to give evidence on Tuesday to present its side of the story.
Both the Pentagon and the state department have already launched a wider review of the way private security firms operate in Iraq.
Peter Singer, a defence analyst with the Brookings Institution, says there are nearly 50,000 armed private security guards working in Iraq.
This is, in essence, a private army with no clear chain of command and no clear rules of accountability, an army that Mr Singer believes may not always share the same goals as the US military of how best to win the war.
He believes private security firms are harming the counter-insurgency and undermining efforts to win "hearts and minds".
Danger and money
It is lucrative work. The US state department paid Blackwater alone more than $800m between 2004 and 2006.
But it is also dangerous - several Blackwater employees have lost their lives.
Kelly McCann has been on both sides of the fence. A former US marine, he is now the president of Kroll's Security Group, a firm with plenty of experience in private security work in some of the most dangerous parts of the world.
Iraqis are very angry - from people in the street to PM Nouri Maliki
He fears that the controversy surrounding Blackwater may unfairly tarnish an entire profession.
He says most of those who work as private security contractors put their lives at risk to do a mission.
"Can you say or generalise that everyone in that industry has some kind of evil motivation or is motivated to behave badly? I don't think you could say that about any organisation. Certainly not mine."
However, it is hard to see how this industry can survive unscathed.
Whatever the truth behind the events of 16 September, private security guards already suffer from an image problem - condemned by critics as mere mercenaries motivated by danger and money.