The Department of Justice (DOJ) is a federal department that is a part of the executive branch. This department deals with the legal work of the federal government.
The DOJ has over 100,000 employees, and deals with matters that involve the federal government, such as civil and antitrust violations, environmental lawsuits, etc.
The Department of Justice is a very powerful organization and possesses a budget of $30 billion. This department does things such as filing lawsuits on behalf of the federal government. It also prosecutes criminals and deals with non-criminal offenses.
Lawyers, criminal investigators and law enforcement agents are all on the payroll of the DOJ. The U.S. Attorney General is at the head of the department and is its top officer. Assistant Attorney Generals lead the sub-departments.