BAY ST. LOUIS, Miss. -- The FBI has joined the search for a Gulf Coast woman charged with murder for allegedly dumping a pot of heated cooking oil on her sleeping husband last month.

Investigators said 45-year-old Edna May Sanders fled the couple's home with their two children on July 28 after allegedly dumping a pot of hot grease on her husband, leaving him with third-degree burns on more than half of his body.

Sherman Sanders spent a week in the burn center at the University of South Alabama. After his death this past Friday, county investigators intensified the search for his wife.

Authorities said the two were married only a short time.

FBI Special Agent Jason Pack confirmed that federal authorities will provide assistance to the Hancock County Sheriff's Department in the nationwide search. Hancock investigators said because Sanders may have crossed state lines, the FBI can lend its resources. Hancock investigators think Sanders is probably seeking shelter with family in Louisiana or Texas.

Police believe Edna Sanders heated about two quarts of household cooking oil on the stove and allowed the grease to reach a simmer while her husband slipped into a sound sleep. Then, she poured the smoldering grease over his head, face, chest and arms.

The Sun Herald reported that the burns to Sherman's head, face, chest and arms were so severe he had to use a car horn to alert a neighbor that he needed help because he was unable to dial a phone. The man did speak briefly to investigators.

Police have no motive for the killing.

Neighbors said there were no visible signs of marital problems between the Sanders and that the family kept to themselves.

Kenny Hurt, Hancock's chief investigator, said there is no history of domestic violence between the couple at their current address.

The FBI said Sanders fled in a 2001 Pontiac Grand Prix with a retired U.S. Navy license plate.