Three construction supervisors are to blame for two firefighters’ deaths in the condemned Deutsche Bank building, prosecutors told jurors yesterday.

By turning a blind eye to a break in an essential water pipe, “they did the thing that killed those firefighters,” Manhattan prosecutor Joel Seidemann said in a closing argument at the manslaughter trial stemming from the 2007 inferno.

“The evidence . . . woven together paints a mosaic of overwhelming guilt — that but for these wholly reckless acts, these firefighters would be alive today,” Seidemann said.

Jeffrey Melofchik, Salvatore DePaola, Mitchel Alvo and the John Galt Corp. are charged in the only criminal case resulting from the blaze, which killed Joseph Graffagnino, 33, and Robert Beddia, 53. Melofchik was the site’s safety manager; Alvo and DePaola worked for Galt.