A crossbow attacker who shot a doctor in the stomach has been found guilty of attempted murder.

Mark Waterfall was found guilty today of bursting into Suthergrey House Medical Centre in Watford and firing a bolt at Dr Gary Griffith.

Forty-six-year-old Waterfall, of Fairhaven Crescent, South Oxhey, blamed the death of his father Terrence on Dr Griffith, and in act of revenge set about to kill him on the morning of July 10 2018.

St Albans Crown Court heard the crossbow bolt travelled at a speed of 187 feet per second, striking the left side of the doctor’s stomach.

Miraculously, the doctor survived because the bolt had to travel through four layers of cotton shirt.

It was a warm morning and Dr Griffith had loosened his shirt around his waist that morning so it gathered up around his midriff.

It meant Dr Griffith, who has been at Suthergrey for 20 years, was able to pull the arrow out of his stomach.

He told the jury: “Although the wound was gaping, it hadn’t gone into the colon. I had to pull the wound apart to check if it had gone into the bowel. I was still sitting down and I removed the bolt and put it on my desk. I pulled the wound apart to see how far it had gone in.”

Waterfall wrongly blamed the death of his father Terrence firmly on the shoulders of Dr Griffith.

Terrence had visited Dr Griffith five days before the crossbow attack complaining of breathlessness. The doctor found he had fluid in his lung and arranged for him to be taken to Watford General Hospital.

It emerged that Terrence, 76, in fact had a cancer on his lung and the plan for the fluid to be drained could no longer take place and he died a day later.

But Waterfall, who was also a patient at the surgery, blamed the death of his father on Dr Griffith and on the morning of July 10, he drove from him home to Suthergrey, making a stop at a Wetherspoons pub for breakfast.

Armed with a crossbow, which he brought just two weeks earlier, Waterfall entered the surgery and sat down, with the crossbow hidden by two plastic bags, and waited for Dr Griffith to be on his own.

At 11am, while Dr Griffith was sat in his chair, Waterfall walked in, with his fist clenched and said “You killed my father and I am going to kill you.”

Then, from a distance of around five feet, Waterfall fired his crossbow.

Waterfall realised he had no killed the doctor and he fled the surgery, leaving the crossbow on the floor. The doctor followed him, trying to persuade him to go to the police station but Waterfall accused Dr Griffith of murdering his father.

Waterfall, who in the past has experienced mental health issues, including an eating disorder and depression, told the jury he was only trying to “scare” Dr Griffith and did not want to kill him, adding he “aimed down and not towards his face”.

After the defendant’s arrest, said the prosecutor, police officers discovered he had documented his anger at the treatment given to his father and himself in a number of video and audio recordings he had made.

A USB stick that was strapped to his toe on his arrest was also found to contain information “files” in which he expressed his anger.

At the beginning of the trial, Waterfall admitted a charge of wounding Dr Griffith with intent.

Trial Judge Stephen Warner adjourned the sentencing for the preparation of reports, including a psychiatric report.

Waterfall will be sentenced next month.