John L. Plummer, 84, co-founder of Plummer Precision Optics Co. of Pennsburg, Pa., died Oct. 31. He was best known for helping to develop precision optics for the US Army during World War II.

In September, Plummer, his company and several key officers were sued in US District Court in Philadelphia for allegedly selling defective parts to government defense contractors over a 10-year period. Plummer denied any wrongdoing.

Prosecutors said the case against company officers Walter Lagger and Max Haskins would continue. The civil case was originally filed by a former Plummer Precision Optics executive under a federal whistle-blower statute.