The troubled past of the doctor who was dragged off United Airlines in an incident which has plunged the company into crisis is revealed in official documents - including his felony drugs conviction and need for 'anger management'.

Dr David Dao had a past of illicit gay sex with a patient in return for giving, and tested positive for drugs, official documents reveal.

The medic, who specializes in lung disorders, was accused of refusing to give up his seat on Sunday's United Express flight UA3411 flight from Chicago to Louisville for the airline's staff.

Cellphone footage of the Vietnamese-born grandfather's ejection has caused an uproar with critics claiming officers were heavy-handed in taking the senior from the flight.

The doctor spoke to WLKY and told them 'everything' was injured.

Dr Dao has not yet sued the airline but it is clear that if he did, the documents would likely be used by United in their attempt to defend their actions.

But that would only intensify criticism of its treatment of Dr. Dao, with social media users saying his past is no justification for his brutal treatment on the plane.

The row deepened on Tuesday as DailyMail.com revealed how United told its staff that the doctor 'tried to strike law enforcement'. That version of events is not apparently supported by videos taken by other passengers.

The disclosure of what they said to their own staff came after United's CEO, Oscar Munoz, was accused of being 'tone-deaf' for his non-apology to the doctor.

United lost $800 million of its value as shares plunged on Wall Street in the wake of the PR disaster.

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Dr David Dao has been revealed as the man who was dragged from a United flight in Chicago on Sunday. He is pictured with his wife, Teresa, and their grandchildren. It was his wife who alerted authorities to his inappropriate relationship with a patient

Dr David Dao has been revealed as the man who was dragged from a United flight in Chicago on Sunday. He is pictured with his wife, Teresa, and one of their grandchildren. It was his wife who alerted authorities to his inappropriate relationship with a patient

Beaten and bloodied: Dr Dao is pictured bleeding from the mouth after he was body slammed by cops and dragged off the overbooked United flight at Chicago O'Hare

Screaming: The man who had refused to to give up his seat on the overbooked United flight from Chicago to Louisville on Sunday night was dragged off the plane by three cops

What United claimed: The document attached to his passenger file which claimed Dr David Dao, 69, a grandfather, had tried to strike police officers

WHAT THE PSYCHIATRIST FOUND An official report detailed the findings of medical exams performed on Dr Dao and spelled out concerns over his mental state. A court case brought by him would inevitably have to consider whether the documents could be used by United. Among the findings were: Dr. Mary Gannon 'noted that Dr. Dao "lacked the foundation to navigate difficult situations, both interpersonally and in a complex profession". Dr.Gannon noted a need to control, avoidance, withholding information and magical thinking as problematic.' The report went on: 'Dr. Montgomery noted that Dr. Dao appeared to have difficulties with information processing. Neuropsychological screening did not suggest gross difficulties. 'However, in reviewing records, it was noted that Dr. Dao tends to have poor decision-making despite his overall level of ability. 'His choices have resulted in significant consequences over the years yet he continues·to function in this manner. 'He is generally not forthright regarding details of events unless challenged and at times he will tell different versions of a story to different interviewers. ' Later in the report it found: 'As far back as April, 2002, Dr. Brady notes " ... he would unilaterally chose to do his own thing'. 'This remains a concern to this day and without a high degree of structure and accountability he is at risk for further boundary related practice issues.' Advertisement

The father of five, who has won sympathy globally over the incident, was given a suspended jail sentence for illegally obtaining and trafficking controlled substances by fraud and deceit.

He was also found to have engaged in sex with a male patient- Brian Case, who he knew from the church they both attended - and then supplied him with drugs, including Oxycontin, in exchange for sexual favors.

The sexual liaisons, which happened in motel rooms, were recorded by undercover agents. He paid $200 in cash each time he met Case.

Case said he believed that Dr. Dao wanted to hook him on drugs so he would keep meeting him for gay sex.

Dr. Dao was arrested when Case agreed to go undercover. Even when he was caught with his shirt off and pants unbuckled, he denied he was there for gay sex with Case.

The secret sex and drugs life of the doctor first came to light in July 2003 when police alerted the Kentucky Board of Medical Licensure of the allegations against him.

In October 2003 he was indicted by a Jefferson County Grand Jury for 'criminal acts of trafficking in a controlled substance, obtaining drugs by fraud and deceit, and unauthorized prescribing, dispensing or administering of controlled substances'.

His medical license was suspended later that month.

Dr Dao underwent intense scrutiny and re-training for several years after his convictions. He also appealed unsuccessfully against conviction, including claiming the undercover video of him semi-naked broke his expectation of privacy.

His wife Dr. Theresa Dao, who was with him on the ill-fated flight, has stood by him.

She first alerted the medical authorities about her suspicions of her husband’s involvement with a patient.

In 2015, his medical license was partially re-instated with restrictions placed on his access to patients.

The findings were revealed by the Kentucky Board of Medical Licensure in June last year and stipulated that monitoring had to be continued of the doctor’s behavior.

It was found that Dr. Dao had become sexually involved with a patient who had been referred to his practice, who was known as 'Patient A'. He was named in criminal court as Case, who was 26 at the time, less than half the doctor's age.

The board stated: 'During the initial evaluation, the licensee performed a complete physical examination, including a genital examination, for Patient A who had been referred for collapsed lungs and chest pain.'

The board's finding went on: 'Shortly after his first appointment, the licensee made Patient A his office manager; according to Patient A, he quit that job because of inappropriate remarks made by the licensee.

'After he quit, the licensee pursued him aggressively, finally arranging to provide controlled substance prescriptions to him in exchange for sexual acts.

'This continued for some time, with Patient A and the licensee meeting at hotel rooms and some of these meetings were recorded.

'At some point, the licensee began splitting some of the prescriptions with Patient A and gave Patient A money to fill the prescriptions.

Stock plunge: The battering taken by United Airlines was obvious in its five-day performance, which showed how it plunged as Wall Street opened

Back practicing: How Dr Dao was able to return to medicine after his felony conviction

Winning big: While he was suspended from practicing, he became a semi-professional poker player, and is said to have won a total of $234,664 since 2006, according to PokerNews.

United Airlines' CEO Oscar Munoz (pictured in June 2016) has come under fire for his response to the scandal

Home: Despite the gay sex revelations, Dr. David Dao continues to share the family home in Elizabethtown, KY, with his wife Teresa, who alerted authorities to her concerns

UNITED CEO OSCAR MUNOZ's LATEST STATEMENT TO STAFF Dear team The truly horrific event that occurred on this flight has elicted many responses from all of us: outrage, anger, disappointment. I share all of those sentiments, and one above all: my deepest apologies for what happened. Like you, I continue to be disturbed by what happened on this flight and I deeply apologize to the customer forcibly removed and to all the customers aboard. No one should ever be mistreated this way. I want you to know that we take full responsibility and we will work to make it right. It’s never too late to do the right thing. I have committed to our customers and our employees that we are going to fix what’s broken so this never happens again. This will include a thorough review of crew movement, our policies incentivizing volunteers in these situations, how we handle oversold situations and an examination of how we partner with airport authorities and local law enforcement. We’ll communicate the results of our review by April 30th. I promise you we will do better. Advertisement

'The licensee also assisted Patient A to fill the controlled substances prescriptions in a variety of names of other persons.

'Police were able to identify approximately 33 fraudulent prescriptions as part of their investigation with Patient A's assistance.

'The police were able to put together a sufficient case to arrest the licensee and bring charges against him in two counties.'

GAY SEX, DRUGS AND FELONY SHAME OF THE UNITED DOCTOR What the Kentucky Board of Kentucky Board of Medical Licensure found: 'During the Board's investigation into the criminal charges against the licensee, the Board learned that the licensee had become sexually interested in a patient who had been referred to his practice, Patient A During the initial evaluation, the licensee perfonned a complete physical examination, including a genital examination, for Patient A who had been referred for collapsed lungs and chest pain; shortly after his first appointment, the licensee made Patient A his office manager; according to Patient A, he quit that job Because of inappropriate remarks made by the licensee; after he quit, the licensee pursued him aggressively, finally arranging to provide controlled substance prescriptions to him in exchange for sexual acts

This continued for some time, with Patient A and the licensee meeting at hotel rooms and some of these meetings were recorded; at some point, the licensee began splitting some of the prescriptions with Patient A and gave Patient A money to fill the prescriptions

the licensee also assisted Patient A to fill the controlled substances prescriptions in a variety of names of other persons

Police were able to identify approximately 33 fraudulent prescriptions as part of their investigation

With Patient A's assistance, the police were able to put together a sufficient case to arrest the licensee and bring charges against him in two counties

Around the same time, the licensee was placed on a corrective action plan by Hardin Memorial Hospital due to disruptive conduct and referred to the Kentucky Physicians Health Foundation ("the Foundation'') for evaluation and anger management

After his arrest, the licensee was tested by the hospital and tested positive for Ultramfframadol

As a result of the drug test results and the criminal charges, the licensee's hospital privileges became suspended on September 13, 2003. Advertisement

The Hardin Memorial Hospital, where he worked, placed him on ' a corrective action plan by due to disruptive conduct'.

He was also referred to the Kentucky Physicians Health Foundation for 'evaluation and anger management'.

He was also tested positive for Ultram/framadol and had his doctor's license suspended.

In November 2004 a jury convicted him on felony counts of Obtaining drugs by fraud and deceit. The jury recommended a sentence of two years and eight months on each felony count.

In January, 2005, Dao was sentenced in Jefferson Circuit Court to two years and eight months on each felony conviction. He was allowed a five year supervised probation.

While he was suspended from practicing, he became a semi-professional poker player, and is said to have won a total of $234,664 since 2006, according to Poker News.

But in May 2007 he was assessed as to his medical and clinical ability.

He was found to be possessing medical knowledge 'that was outdated and also contained gaps that would not likely be fully explained by his time away from practice.'

The board added: 'His areas of relative strength included occupational lung disease and pulmonary embolism.

'Dr. Dao's knowledge of current pharmacology was deficient He demonstrated some deficits that were surprising based on the common nature of the disorders.'

The doctor underwent an ' Educational Intervention Plan' where he was re-trained and his progress monitored.

During his assessments the report said Dr. Dao denied paying for sex. Yet he indicated that he deducted monies owed to him... for sexual favors.

He denied trading drugs for sex while admitting to prescribing narcotics to the man while they engaged in a sexual relationship.

'Dr. Dao continues to maintain a pattern of deception that is inconsistent with the level of accountability necessary for a practicing physician.'

His bid to renew his medical work was rejected because of the sex and lies he had been found guilty of as well as his outdated practices.

'It is the opinion of the assessment team that Dr. Dao is not safe to practice medicine at this time. This opinion is offered within reasonable certainty and based upon available information.'

Two years later he returned to the same evaluator where a doctor Mary Gannon noted that Dr. Dao 'lacked the foundation to navigate difficult situations, both interpersonally and in a complex profession'.

Dr. Gannon noted a need to control, avoidance, withholding information and 'magical thinking' as problematic. She also opined re-instatement of Dr. Dao's medical license as the primary motivation for therapy.

During this evaluation Dr. Dao stated that regaining his medical license was a matter of 'family honor.'

Four of his five children are doctors. His wife Teresa, 69, is a pediatrician who trained at Ho Chi Minh University in Saigon and also practices in Elizabethtown, Kentucky - about 40 miles south of Louisville.

Their eldest son Tim, 34, practices medicine in Texas; their second son Ben, 31, is a medical graduate; their daughter Christine, 33, is a doctor in Durham, NC; and their youngster daughter Angela, 27, is a medical graduate of the University of Kentucky.

Their other daughter, Crystal – Christine's twin – is a married mother in Barrington, Illinois.

Dr Dao has previously worked at Hardin Memorial Hospital and owned a medical practice.

His identity has been revealed after United CEO Oscar Munoz doubled down on his airline crew's decision to remove an elderly passenger, claiming he was 'disruptive and belligerent'.

The airline is facing a furious backlash after footage emerged of the 69-year-old, bleeding heavily as he was pulled from the jet.

Amidst the anger, Munoz issued a public apology saying he 'apologized for having to re-accommodate these customers.'

But in a private email to employees, the CEO defended the crew's actions, calling the passenger 'disruptive and belligerent' and praising his staff for going 'above and beyond'.

Backlash likely: The reaction to revelations of the criminal past of the doctor suggests that United would risk further opprobrium if they used it in a potential court case

United CEO Oscar Munoz has doubled down on his airline crew's decision to remove an elderly passenger, claiming he was 'disruptive and belligerent'

Social media erupted immediately, labeling Munoz and United 'tone deaf' and 'condescending'.

Munoz said that while he was 'upset' to hear about the man being violently dragged off the flight, that airline crew had simply been following 'established procedures.'

The CEO described how flight crews had offered up to $1,000 in compensation for anyone willing to catch the next flight before approaching the passenger to 'explain apologetically' that he was being denied boarding.

He had then 'raised his voice and refused to comply' with the crew's requests to leave the aircraft, and became increasingly 'disruptive and belligerent,' he said.

'Our agents were left with no choice, but to call Chicago Aviation Security Officers to assist in removing the customer from the flight, he repeatedly decline to leave.'

Munoz added that the passenger refused to comply with the officers who then 'physically removed him from the flight as he continued to resist – running back onto the aircraft in defiance of both out crew and security officials.'

The comments have sparked outrage online with people claiming that the CEO was attempting to shift blame to the police

'While I deeply regret this situation arose, I also emphatically stand behind all of you, and I want to commend you for continuing to go above and beyond to ensure we fly right,' he said.

The CEO did, however, concede that there were 'lessons we can learn' from the experience and that United will continue to look into the incident.

He also had a final reminder that treating customers with 'respect and dignity' should be matter of course, 'no matter how challenging the situation.'

The comments have sparked outrage online with people claiming that the CEO was attempting to shift blame to the police.

Others said that 'lousy protocol' was never an excuse for a 69-year-old man beating left bloodied by security.

'Beating and bloodying a 69 year-old doctor is 'protocol' @United ?' one Twitter user asked.

Distressing: Children were crying in distress as the three officers manhandled the man out of his seat. Passengers had been offered $800 to take a flight the next day but none volunteered

Another said that Munoz was 'trying to shift blame to police/aviation security (not United employees). The public doesn't make a distinction.'

Nicholas Kristof added: 'In any big company, staff will sometimes do stupid things. At United, the CEO then endorses the stupidity and claims it as company policy!'

Others pointed out that the customer had also appeared to have followed 'protocol' right up until he was dragged off the plane.

HOW DOES UNITED DECIDE WHO GETS BUMPED FROM OVERBOOKED FLIGHTS? United's contract of carriage states that passengers to be forcibly taken off a flight in the event of overbooking will be 'determined based on a passenger's fare class, itinerary, status of frequent flyer program membership, and the time in which the passenger presents him/herself for check-in without advanced seat assignment.' That means that if you have a certain type of fare class, checked in early, have a flier status such as gold, or even just own a barely used frequent flier card, you are less likely to be bumped. But passengers taking advantage of budget seats appear to be of less value to the airline. Advertisement

'#United Pay for your ticket, sit down, get attacked, bloodied and humiliated. And the CEO is now saying the person deserved it. #SHAME,' one Twitter user wrote.

'No accountability for lousy protocol,' another added. 'It will be a cold day in Hades before I allow these lackwits to fly me anywhere.#BoycottUnitedAirlines.'

An airport cop who allegedly body-slammed the passenger was put on leave today - as his bosses condemned his actions amid mounting outrage over video of the incident.

The Chicago Department of Aviation said it 'obviously' did not condone the behavior of the security officer who was filmed slamming the man into an arm rest, knocking him unconscious and dragging him away by his arms as he bled from the mouth at O'Hare.

Another clip shows the dazed man chants 'just kill me, just kill me' as blood pours from his mouth.

In his public apology, Munoz said today: 'This is an upsetting event to all of us here at United. I apologize for having to re-accommodate these customers.

'Our team is moving with a sense of urgency to work with the authorities and conduct our own detailed review of what happened. We are also reaching out to this passenger to talk directly to him and further address and resolve this situation.'

The aviation department released a statement to the Chicago Sun-Times, which read: 'The incident on United flight 3411 was not in accordance with our standard operating procedure and the actions of the aviation security officer are obviously not condoned by the Department.

Unhinged: The man claimed to be a doctor and screamed wildly and he was manhandled by the cops

'That officer has been placed on leave effective today pending a thorough review of the situation.'

One passenger also told the Washington Post the man claimed as he was being dragged off the plane he was chosen because of his ethnicity.

'He said, more or less, 'I'm being selected because I'm Chinese',' the passenger told the Post.

The same passenger went on to tell the newspaper a United official walked onto the plane during the incident and said the plane would not be taking off until four passengers disembarked so the employees could fit on.

He said the official announced: 'We have United employees that need to fly to Louisville tonight. … This flight's not leaving until four people get off.'

'That rubbed some people the wrong way,' Tyler Bridges said, recounting the comment.