Skeletal remains of a man wearing a suit and tie were found sitting in a burial vault with no casket in sight at a historic black Illinois cemetery where workers allegedly dug up bodies and dumped them in a scheme to resell plots, officials said Friday. Cook County Sheriff Tom Dart said detectives were exhuming that grave site and two others, including one where two burial vaults were stacked on top of each other, the first proof that the alleged plot involved burying bodies on already-occupied grave sites. Four workers were charged in the alleged scheme, which authorities say stretches back at least four years and netted $300,000. Dart said authorities continue to find more bones and other evidence of the scheme. As many as a dozen vaults, including one for an infant, also were found recently in a heavily wooded area after detectives removed brush and trees from the site, officials said. Dart said more bones were found in a 4-5 feet-high mound of earth that appears to be man-made. Authorities say they believe at least 300 graves were dug up, and so far, more than 1,000 bones have been found.