Three people whose building violations four years ago in the Bronx allegedly laid the groundwork for the death of two city firefighters went on trial Monday.

Prosecutors say the two FDNY firefighters, Curtis Meyran, 46, and John Bellew, 37, were forced to jump from the fourth floor of a building on East 178th Street in 2005. The incident, which is known as "Black Sunday," happened because the building's fire escape was illegally blocked, prosecutors say.

Prosecutors also claim the illegally divided building hampered the efforts of the firefighters, confused them and left them with little choice but to jump to their deaths.

Rafael Castillo, Caridad Coste and Cesar Rios face counts of second-degree manslaughter, criminally negligent homicide and reckless endangerment in the case.

Tenant: 'Black Sunday' repeat possible at building