Cases are decided by immigration judges, who are appointed by the Attorney General and are part of the Department of Justice.
Removal proceedings are prosecuted by attorneys from the Department of Homeland Security ("DHS"), or more specifically, U.S. Immigration and Customs Enforcement.
The Notice to Appear is a dated document served by a U.S. immigration official (typically U.S. Immigration and Customs Enforcement or U.S. Customs and Border Protection) to a person suspected of entering the United States without inspection, remaining in the United States beyond the terms permitted by a visa, committing certain crimes which result in removability even if in lawful status, or otherwise being present in the United States unlawfully.
The merits hearing may be a matter of days or perhaps even more than a year later, depending on the type of relief requested and the particular court's docket.
This decision might be oral and given on the same day as the merits hearing, or written and served by mail on all parties at a later date.
A respondent with a final order of removal from an immigration judge is susceptible to being arrested and deported from the United States at any time.
However, most immigration courts have set up programs where pro bono (free, volunteer) attorneys are available on the day of the master calendar hearing.
However, the BIA does not generally accept new evidence regarding the original case, but instead, simply aims to determine whether the previous court made an incorrect judgment based on the law or the facts available to it at that time.
There is more flexibility regarding the sort of evidence that may be presented in these appeals but the court generally focuses on whether the original BIA decision was made correctly based on the information available, rather than re-adjudicating the facts involved.
People who are found guilty through Operation Streamline courts generally have to spend a few months in prison, after which they are handed over to immigration enforcement.