Three engineers and the developer of a defective construction method were convicted Sunday in a Jerusalem court on charges of causing death by negligence for their roles in a Jerusalem banquet hall collapse five years ago. Twenty-three people were killed and nearly 400 were injured when the Versailles banquet hall collapsed during a wedding on May 24, 2001. It was the worst non-war related accident in the country's history. The developer of the "Pal-Kal" method of construction, Eli Ron, and engineers Uri Pessah, Dan Shefer and Shimon Kaufman were all found guilty by the Jerusalem District Court on Sunday. The court said in its ruling it had been proven that the Pal-Kal system was substandard and dangerous, and that Ron was negligent in distributing and selling it. The court also found that Ron had continued using the method despite warnings of intrinsic flaws. "A reasonable man... could and should have been aware of these flaws and the danger in the Pal-Kal system," Judge Moshe Gal wrote in the ruling. "The wheels of justice turn slowly," said Avi Cohen, who lost his daughter Shonit in the collapse, "but finally, after 1,585 days of legal deliberations, justice has been meted out." In November 2005, Versailles co-owners Avraham Adi and Efraim Adiv were sentenced to two and a half years in prison after being convicted on similar charges. Police and Technion-Israel Institute of Technology engineers have said that a combination of shoddy construction, reckless renovation, building violations and criminal negligence led to the collapse. Pal-Kal is a cheap, lightweight construction method that uses metal plates and thin layers of cement. It was popular in the 1980s and was banned by the Israel Standards Institute in 1996 because it did not meet safety requirements. Hundreds of buildings - including dozens of banquet halls, schools and shopping centers - were built using the process. In 1998, the Interior Ministry instructed all municipalities and local councils to inspect all buildings constructed using the method, but most ignored the directive, including the Jerusalem Municipality. A state commission of inquiry into the safety of public buildings, set up in the wake of the Versailles collapse, concluded in December 2003 that another Pal-Kal disaster was just a matter of time, since the government had largely failed to act on the issue.