Two of blues legend B.B. King's daughters have accused his two closest aides of poisoning him.
Karen Williams and Patty King allege in documents provided by their lawyer to The Associated Press that King's business manager, LaVerne Toney, and his personal assistant, Myron Johnson, killed their father.
Clark County Coroner John Fudenberg said a post-mortem was performed on Sunday on King's embalmed body but test results will take up to eight weeks.
Las Vegas police Lt Ray Steiber confirmed that homicide detectives are investigating.
The investigation should not delay planned memorials this week in Memphis, Tennessee, and Indianola, Mississippi.
Toney and Johnson each declined to comment.
At least 11 people died and around 180 were injured after a tornado ripped through the northern Mexican border city of Ciudad Acuna.
Mayor Evaristo Lenin Perez said as many as 350 homes were damaged and numerous cars damaged in the city that lies across the Rio Grande from Del Rio, Texas, officials said.
"We're working on clearing the debris of the destroyed buildings and cars that were displaced," said Francisco Martinez, the deputy minister for Civil Protection in Coahuila.
Prime Minister David Cameron has begun talks with European Commission president Jean-Claude Juncker as he begins efforts to renegotiate the UK's relations with the EU.
Greeting Mr Juncker at Chequers, Mr Cameron told him they were meeting in the room reputedly used by Winston Churchill to write some of his most famous wartime speeches.
"Think of 'we'll fight them on the beaches' " he told him before they sat down for a dinner of pork belly, bacon and seasonal vegetables - promising to later show him the ex-premier's brandy glass.
Exchanging pleasantries before getting down to talks, Mr Cameron noted that it was a bank holiday, adding: "My wife has taken the children away on holiday and I am working."
Murder suspect Jed Allen is believed to have been found dead by police.
Detectives had been hunting the 21-year-old since Friday following the discovery of the bodies of his mother, stepfather and stepsister.
Janet Jordon, 48, Philip Howard, 44, and their six-year-old daughter Derin were found stabbed at their home in Didcot, Oxfordshire.
Thames Valley Police said the body was found in woodland barely a mile from Oxford University parks just after 5pm.
They added they are not seeking anyone else in connection with the deaths.