The father of the 21-year-old man arrested for the El Paso shooting massacre was a drug addict for almost 40 years and is now an energy healer who claims to have had visions of Jesus Christ and his dead grandmother, DailyMail.com can reveal.

Patrick Crusius allegedly killed at least 20 people and injured 26 on a gun rampage which began in a Walmart parking lot in El Paso, Texas on Saturday morning before he was arrested by police.

His father, Bryan Crusius, 63, revealed in a 2014 memoir details of the broken home his son grew up in, confessing to decades of drug and alcohol abuse that led to the breakup of both his first marriage and his 18-year relationship with the alleged shooter’s mother.

The book offers some insight into the mass shooter’s upbringing - but not what turned him into an apparently white supremacist-inspired multiple murderer who was cold-blooded enough to make sure he was taken alive.

Bryan Crusius, 63, (left), the father of accused El Paso Walmart shooter Patrick Crusius (right), wrote a memoir detailing his almost 40 years of drug and alcohol addiction which he says tore apart both his marriages. Byran pictured left on his now defunct YouTube channel

He revealed in a 2014 memoir details of the broken home his son grew up in, confessing to decades of drug and alcohol abuse that led to the breakup of both his first marriage and his 18-year relationship with the alleged shooter’s mother

The book offers some insight into the mass shooter’s upbringing - but not what turned him into a killer. Bryan Crusius pictured front with his children including alleged shooter Patrick Crusius (far left), his twin sister Emily (center) and brother Bryan (right) in 2012

Family: Bryan pictured with his kids Emily, Bryan and Patrick Crusius (from left to right) in 2014

The shooter apparently uploaded a racist ‘manifesto’ just before starting the attacking.

The 2,300 word screed, attributed to the author P.Crucius on one website, speaks of a perceived ‘Hispanic invasion of Texas’; a detailed plan to segregate ethnic minorities into separate territories of the country; and expresses a belief that white people will soon be ‘ethnically replaced.’

His father’s book at least suggest that lengthy and rambling postings are in the family.

His 2014 memoir Life Enthusiasm: A Path to Purpose Beyond Recovery pictured above

Crusius Sr, who now works as a licensed therapist and ‘energy and sound medicine practitioner’ in Allen, Texas, claims in the rambling memoir to have had a conversation with Jesus in a vision and had a spiritual encounter with his dead grandmother, Mabel.

The book, entitled Life Enthusiasm: A Path to Purpose Beyond Recovery, reveals how Crusius Sr struggled with mental health problems that impacted his four children - the son from his first marriage, Austin, who he left in California with his ex-wife Kathleen, and his three children from his second marriage to Lori - Patrick; his twin sister Emily; and their older brother Blake.

A teaser on the back of the $12.95 book’s cover says that before writing his memoir he had ‘descended into a profound and unsustainable apathy in which life no longer seemed purposeful or worthwhile’ after ‘thirty years of dependence on mind-altering chemicals’.

The therapist, who says he has now kicked drugs and drink, through ‘a unique synthesis of traditional talk therapy with multiple energy modalities’ which he says ‘infuses spiritual principles, sound healing, guided meditation, life force energy, and other eclectic methods with traditional talk therapy.’

In the first chapter, the father-of-four admits to being ‘an addict for roughly forty years’.

According to his book, Bryan is a licensed therapist and energy and sound medicine practitioner. His book details his battle addiction and its impact on his children

Bryan Crusius' website pictured above where he shares advice on addiction and codependence

His Twitter page pictured above where he says he teaches meditation and energy healing

‘I lived a life of pretense in a kind of dream, alternating between the lows of apathy and hopelessness and the highs of material success,’ he wrote. ‘I have quit and relapsed countless times.’

The therapist revealed that his drinking and drug-taking led his second wife initially to banish him to a separate quarter of the family home in Allen, Texas, and finally to divorce and kick him out the house when Patrick was 12-years-old.

‘In the last quarter of 2011, after many months of living alone upstairs my spouse of eighteen years knocked on the door and handed me divorce papers,’ Crusius Sr wrote.

‘Every time I thought of living apart from my three children I would break down into total misery. I wondered why the world was so unfair. What events could justify separation of a father from his children?’

The therapist detailed how he was a veteran user of hallucinogens by age 16, and progressed to benzodiazepines, anti-depressants - including Vicodin - and prescription drugs commonly prescribed for people with ADHD.

His book reveals how Crusius Sr struggled with mental health problems that impacted his four children - the son from his first marriage, Austin, who he left in California with his ex-wife Kathleen, and his three children from his second marriage to Lori - Patrick; his twin sister Emily; and their older brother Blake

The majority of the father’s memoir is a rambling account of his various hallucinations and ‘visions’ while meditating with other spiritualists and ‘energy healers’. In one bizarre session, he recounts speaking with Jesus

‘I was always the one daring everyone else to go over the top in the partying category by taking the extreme amounts of whatever we had, whether Quaaludes, alcohol, magic mushrooms, or something else,’ he wrote.

Even as a father of young children and a practicing therapist counselling patients on their addiction problems, Crusius Sr admitted he continued to abuse drugs himself.

The breakdown of his marriage had repercussions for his twin young children, who in one incident were left home alone at Christmas aged 13 when his wife left for Oklahoma.

Crusius Sr wrote that on December 23 he was driving to work to give a patient a mental health assessment when he got a call from his teenage daughter Emily, multiple murderer Patrick’s twin sister, telling him the news.

‘It was my daughter wanting to know when I would be home because she needed a ride to a friend’s house.

‘I asked, “Where’s your mom? Can she take you?” An uncomfortable silence filled the air and finally she replied. “She left this morning for Oklahoma.”

Crusius Sr wrote that on December 23 he was driving to work to give a patient a mental health assessment when he got a call from his teenage daughter Emily, multiple murderer Patrick’s twin sister, telling him the news.

‘It was my daughter wanting to know when I would be home because she needed a ride to a friend’s house.

A former neighbor of Crusius, Leigh Ann Locascio, said Patrick Crusius was 'very much a loner, very stand-offish' and 'didn't interact a whole lot with anyone'. The suspect is seen in a yearbook photo

‘I asked, “Where’s your mom? Can she take you?” An uncomfortable silence filled the air and finally she replied. “She left this morning for Oklahoma.”

‘“What?” I said, feeling quite surprised. She had not told me of any trip or advised me that she was leaving.

‘What was shocking on the surface was to realize that my spouse had taken off without leaving an adult in charge.’

The father reacted bizarrely to the news, immediately pulling into a ‘major warehouse store’ and attempting to steal a computer hard drive.

He was apprehended by security guards and spent several days in county jail, leaving his three children to fend for themselves on Christmas Day.

When he eventually returned home, Crusius Sr wrote how his eldest son Blake was shocked at his appearance.

‘My seventeen year old son stared at me in disbelief. I sheepishly went up the stairs in a cloud of shame. My behavior of the last few years had placed him in a state of fear and uncertainty. He was the oldest and had taken on responsibility by default as the man of the house,’ the father wrote.

The majority of the father’s memoir is a rambling account of his various hallucinations and ‘visions’ while meditating with other spiritualists and ‘energy healers’.

In one bizarre session, he recounts speaking with Jesus.

‘Christ greeted me with a smile. He pulled his robe aside again with his right hand to reveal the flaming heart of love and compassion. He addressed me thus: “Bryan, you have chosen the Path of the Heart,”’ the licensed therapist wrote.

On Sunday, the alleged El Paso Walmart shooter’s grandfather got into an altercation with an FBI agent who showed up at his home, where Patrick Crusius lived for at least two years.

Larry Brown, 77, shouted ‘get the hell out of here’ at an FBI agent who approached his Allen, Texas home on Sunday morning.

The grandfather also refused to speak to media.

A neighbor told DailyMail.com the grandfather and his wife Cynthia were a ‘retired, nice older couple, really nice people’, but that he only saw the 21-year-old ‘in passing’.

‘We only saw him walking the dogs,’ said the neighbor. ‘The kids would say hello, and he’d say hello back.

‘Three weeks ago I saw him and a couple of friends out flying a drone. They just looked normal. The whole thing is very strange.

‘We’ve seen him off and on the past couple of years.’

The neighbor said local and federal law enforcement and media descended on the quiet suburban street Saturday morning shortly after the shooting in El Paso.

‘We walked out into the yard and immediately we were swarmed with cameras,’ he said. ‘Our neighbors front yard was full of people, then the police came. The FBI came and then local police shut the whole area down.

‘We heard helicopters all night. I had to cross through two layers of security to go to the gym.’

Residents of the former Crusius family home, where the alleged shooter lived with his twin sister, older brother and parents before they divorced, said they bought the house from the family about 18 months ago, but had no personal contact with them. Property records show the house was sold in March 2018 for $385,000.