Most states have laws preventing someone who has murdered the victim from inheriting assets from the diseased. However, the challenge is determining who is responsible for the death, according to the Daily Mail in "Heir, 23, accused of murdering his millionaire grandfather, 87 and sinking the boat his mother was sailing off Rhode Island could still get $7 million inheritance despite relatives legal fight to stop him."
An estate battle occurred in New Hampshire in 2013, when millionaire John Chakalos was found shot to death. Prior to his death, his grandson Nathan Carman had purchased a weapon and bullets of the same caliber as the one that shot Chakalos.
The estate was divided equally between Chakalos' four daughters, including Carman's mother Linda Carman.
In 2016, Nathan and Linda Carman went out on a boat. Something happened to the boat and Nathan was eventually found adrift by a Chinese ship, miles away from where he claimed the boat had sunk.
Linda was never found.
Nathan had claimed that he personally repaired holes in the boat to make it seaworthy, but insurance companies in court said the repairs were shoddy.
Linda Carman's three sisters have filed in court to prevent Nathan Carman from receiving any part of his mother's estate.
They accuse their nephew of murdering both his grandfather and his mother for the money.
However, investigations into the deaths remain open and no suspects have been officially named.
Reference: Daily Mail (August 1, 2017) "Heir, 23, accused of murdering his millionaire grandfather, 87 and sinking the boat his mother was sailing off Rhode Island could still get $7 million inheritance despite relatives legal fight to stop him."