A HATE-filled man wrote a letter mapping out a tragic plan to cause serious harm to his step-son before shooting himself, an inquest heard.
Robert Heaven, 61, carried out that plan on Tuesday, December 3 last year, shooting Albert Stewart, his step son, before turning the gun on himself at the family's Orsett home.
At an inquest in Chelmsford on Friday, coroner Caroline Beasley-Murray concluded that Mr Heaven had committed suicide in "a tragic set of circumstances".
It is not clear what the ill-fated grudge was over.
Police attended the property in Henley Road, shortly after 3pm on the day of the incident and found Mr Stewart, at the top of the stairs on the landing. He had been shot several times, but amazingly, survived the ordeal.
The 45-year-old had come home from work early after feeling unwell, before being shot several times by his step-father.
Mr Heaven was found around 15 feet away, in his bed having shot himself through the mouth. He had been drinking, the coroner heard, but only a very small amount.
DI Martin Passmore told the inquest: "There were letters nearby, written by the deceased. They spelt out his intention to seriously harm his step-son and then take his own life."
Mr Heaven also used the letter to warned police not to bother looking for the person who had supplied him with the 2.2 calibre pistol, adding "you will never find him".
That sparked a police probe. DI Passmore added: "We think it had come from America. It hadn't been used in crime in this country. There was an investigation into how it got here, but it dried up."
It is not clear what grudge Mr Heaven was bearing against his step-son - but police are satisfied that no one else was involved in the incident and there were no other witnesses.
Mrs Beasley-Murray concluded: "He [Mr Heaven] obviously felt very strongly and had a grudge against his step son and took an action, knowing it would lead to him taking his own life.
"What a tragic set of circumstances."
Andrew Beardwell, the step-son in law, married to the daughter of Mr Heaven's partner, was at the inquest on behalf of the family.
He said: "This caused huge amounts of grief and continues to do so."