An expecting father died on Sunday after a device he was building for a party focused on revealing his child’s gender exploded, authorities said. New York state police officers responded just before noon to a report of an explosion in the town of Liberty. An investigation showed that Christopher Pekny, 28, was building a device “to be used at a child gender reveal party,” police officials said in a statement. The device exploded, killing Pekny and injuring his brother. Michael Pekny, 27, was rushed to Garnet Medical Center in Middletown. The incident is being probed by the state police, including its Bomb Disposal Unit. The Pekny family owns the Robin Hood Diner in Livingston Manor, New York. “We are deeply saddened and must inform you all of the loss of our dear an[d] beloved Christopher,” the owners said in a Facebook post on Monday, adding that the establishment will be …