The body of Joseph Nelson was found by Alcoa workers in February this year.
Vanderburgh County court records show Grigsby had four felony convictions between 2006 and 2009 on charges including burglary, narcotics, theft and armed robbery.
Indiana Department of Corrections records show that Grigsby was released from prison in December. In September 2009, Grigsby pleaded guilty to burglary and attempted armed robbery and was ordered to serve at least 80 percent of a 10-year sentence by Vanderburgh Circuit Court Magistrate Kelli Fink, according to court records. Department of Corrections records showed Grigsby was paroled Dec. 30.