The arrest of Linda F. Holt came after a 15-month investigation and joint efforts of the Burnsville Police Department, Mississippi Bureau of Investigation and the Tishomingo County Sheriff's Department, said Sheriff Glenn Whitlock.
"There's no one big thing, just hundreds and hundreds of man-hours that led to information and evidence we built up in the case," Whitlock said.
The investigation continues and other arrests are possible.
Holt, 52, of 86 CR 485, was the daughter-in-law of 84-year-old John R. Holt, who was last seen alive at his Eastport Street home in Burnsville on Dec. 22, 2009.
His body was found the next day by his nephew, Andy Floyd, one of his caretakers.
Authorities reported no signs of robbery or forced entry.
The case is expected to be presented to the grand jury at the end of May, the sheriff said.
Contact Lena Mitchell at 287-9822 or email@example.com