Sir Richard Sutton, 83, was pronounced dead at his estate in Higher Langham, near Gillingham, last Wednesday, April 7.
Dorset Police received a report at 7.30pm last Wednesday raising concerns for the welfare of the occupants at the address.
Officers found Sir Richard and a woman in her 60s, believed to be his wife, both with serious injuries.
Sir Richard was pronounced dead at around 9.15pm and an initial post-mortem examination indicated the cause of death was stab wounds to his chest.
The injured woman was airlifted to hospital and remains in a critical condition.
A man was arrested on suspicion of murder in London the same evening.
Thomas Schreiber, 34, Sir Richard’s stepson, was subsequently charged with murder, attempted murder and dangerous driving and was due to appear at Poole Magistrates’ Court today (Monday).
Sir Richard was ranked 435th on the Sunday Times Rich List 2020, with his wealth being valued at £301m.
Among his assets was the Estate at Stainton le Vale.
Detective Inspector Simon Huxter, of Dorset Police’s Major Crime Investigation Team (MCIT), said: “Our thoughts remain with the victims’ family and all of those affected by this terrible incident.
“Following a detailed investigation, we have consulted with the Crown Prosecution Service. As a result, Dorset Police have been authorised to formally charge Thomas Schreiber with the murder of Sir Richard, attempted murder of the injured woman and dangerous driving.
“It is important to stress it would be entirely inappropriate for Dorset Police to comment further ahead of the trial. It is vital the criminal justice system is allowed to follow its course.”