NEW YORK (CBSNewYork/AP) — Testimony has wrapped up in the manslaughter trial stemming from a blaze that killed two firefighters in a condemned Ground Zero skyscraper damaged in the Sept. 11 attacks.

The sole defense witness and prosecutors’ rebuttal witness both finished testifying Monday. Closing arguments are expected to start June 14.

Three construction company supervisors and a firm are on trial.

Prosecutors said the defendants, Mitchel Alvo, Salvatore DePaola and Jeffrey Melofchik, knew a vital firefighting water pipe had broken and didn’t fix it before the August 2007 fire at the former Deutsche Bank building. The defendants say they didn’t recognize the pipe’s significance, and the fire was fed by multiple hazards and regulatory oversights.

The defense witness, a fire safety engineer, pointed to other factors in the blaze. The rebuttal witness, a fire chief, testified the pipe was critical.

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