A man has been charged with the attempted murder of his 86-year-old father and 79-year-old mother.
Former Aston Martin worker Hedley Robinson and his wife Margarete were assaulted at their home in Chicheley Street, Newport Pagnell, on March 24.
Sadly Mr Robinson died three weeks later, on April 14.
A post mortem has taken place, but a cause of death has not yet been established. Further tests will be undertaken, which may take a significant period of time, say police.
Gary Robinson, who is 46, has now been charged with two counts of attempted murder.
He is also charged with one count of racially aggravated public order and one count of assault of an emergency worker.
Police have referred themselves to the Independent Office for Police Conduct over the matter.
Meanwhile Gary Robinson, a landscape gardener, has been remanded in custody by Milton Keynes magistrates.