Four suspects are being held by Nashville police and will be charged with double criminal homicide for the death of both Associate Professor Pierre Colas and his sister, Marie Colas.

Pierre Colas was shot in his East Nashville home on Tuesday night during what seems to be an attempted robbery. Marie Colas had been in critical condition until she died in the Vanderbilt University Medical Center.

Ongoing police investigation led to the discovery on Thursday of several high-ticket items being purchased from local businesses with Colas' identification. The four suspects were smiling and laughing, as seen on surveillance tapes from the stores. Police were able to make the arrest based on a description of the car used during the purchases.Suspects George Eugene Cody, 29, and Gennyfer Dawn Hutcherson, 35, live on West Sharpe Avenue, two blocks away from Colas' home. Suspects Thomas Andrew Reed, 20, and Michael Shane Holloway, 22, were here with a group that sells magazines and were staying at the La Quinta Inn. The four know each other through a relative.

Police are continuing their investigation, and another suspect could be arrested in the coming days. The police could not be reached for comment.