Stephanie Kirk, one of at least three women police believe were killed by William "Clyde" Gibson, was laid to rest over the weekend as the investigation of Gibson ramped up.Kirk, 35, of Charlestown, had been missing for about a month before her body was found in a makeshift grave in the back yard of Gibson's home, police said.Gibson was charged with murder in the deaths of two other women -- Christine Whitis, 75, and Karen Hodella, 45. Hodella was killed in 2002.Gibson has not been charged in connection with Kirk's death.New Albany police announced Friday that they had reassigned officers to help with the Gibson investigation.The FBI has been brought in to search for evidence from as far as 800 miles away from southern Indiana, New Albany police said. Investigators believe that Gibson is a serial killer and that there are more victims."Its certainly possible, if not probable," New Albany Police Chief Sherri Knight told WHAS. "We don't want to make that determination without evidence to support it.Police began investigating Gibson less than a month ago after finding Whitis' body inside his home.Kirk's body was found on April 27.Bloomington police are closely monitoring the investigation nearly a year after missing student Lauren Spierer was last seen.Earlier this month, Bloomington police Capt. Joe Qualters said officials had inquired with New Albany authorities, though there was no evidence of a connection.