The American boss of a $50 billion investment firm was found dead in a locked bedroom in his rented London mansion after a “screaming” argument with his wife, an inquest heard.

Joshua Pack, 51, was co-CEO of the investment giant Fortress – which owns the well known British brands Majestic Wine, Poundstretcher, Punch Pubs and the Curzon cinema chain – and had relocated to London to oversee the firm’s regional growth.

The father-of-four and his wife had had an argument over plane tickets with both threatening to kill themselves, a London court was told.

But senior coroner Professor Fiona Wilcox said she could not be sure Pack’s death was suicide and said it was more likely an “impulsive’ act.

On September 29 last year, he was found in a locked bedroom of the mansion he had rented with his childhood sweetheart Jacqueline in the affluent St John’s Wood area.

Inner West London Coroner’s Court heard the Packs were staying in a rented property while making arrangements to move their household from Dallas, Texas, to London.

The investment banker was preparing to lead the American fund’s push into Europe – a venture tipped to double its value to $100 billion.

At the inquest on May 5, a statement was read out from his wife of 28 years. She said they had an argument the evening before his death after “drinking on and off throughout the day.”

“We were high school sweethearts,” the statement said. “Josh was a devout Catholic who worked so hard to support me and the children, the most important thing in his life. But there were tensions, as in any long-term marriage.”

She described how once, after an argument, Pack had “dramatically” hurled himself off a Swiss hotel balcony into the snow after they argued.

“Josh could be impulsive,” she said. “We had just moved to London from the States. Both of us were incredibly stressed.

“There were a lot of problems with the house and nothing seemed to be working. Josh was excited about his new project at work. I didn’t know the details but I knew it was important.”

She said that on the day before his death they had been drinking and an argument about plane tickets had broken out. Pack was due to fly back to Dallas Tuesday but decided to move his flight forward to Monday to travel alongside his wife.

“When we were walking back to the house, Josh’s PA texted to say that there was a problem with the booking,” his wife said. “We had a heated argument. We went home, I went to the bathroom to calm down; I took off my make-up.

“I came out to see Josh lying on the bed. One of his eyes was much darker than the other. He did not look like himself. We quarrelled again. We started screaming at each other. Josh threw my phone across the room and started hitting himself with it.

“He went to the cupboard and took out a knife. ‘Stick it into me!’ We both said that we would kill ourselves. We’d said it before. I never meant it, and I certainly never thought that Josh meant it.”

Pack said she went to sleep in another room to calm down: “I was not concerned about Josh. We’d fought before. I texted him. He did not respond, but this was nothing unusual.”

When she got up she didn’t know whether her husband was in the house. She phoned him, but there was no answer.

However, his PA told her he had checked in for his flight back to their home in Dallas.

“There was a bedroom upstairs that was locked; nobody could get into it,” said said. “I received a message from Josh’s PA saying that Josh had checked in to his flight.

“I learned later that the airline had done this automatically, but at the time I decided to go straight to the airport.

“I left a message on the group chat with our driver, housekeepers and other staff and asked them to get into the locked room. I asked them to break down the door if necessary.

“In the airport lounge, the housekeeper called me. I asked if Josh was dead and she said yes. I collapsed. Josh was my best friend and I don’t believe he would have wanted to end his life.”

In statements taken by police and read out by the coroner, cleaners at the house said they heard the couple “rowing all night” and “screaming and swearing at each-other” late into Sunday, September 28.

The court heard the final text on Pack’s phone was sent at midnight – a message arranging a pick-up time for the airport the following morning.

Household staff started trying to break into the locked room on Monday afternoon. The room had been locked from the inside and there was no other key. A locksmith was called but was unable to open the door.

Around 3 p.m., the group entered the room via a crawl space in an adjacent bathroom and found Pack’s body.

Detective Sergeant Graham Alger attended the scene and reviewed the evidence on Pack’s seized mobile phone.

The detective told Coroner Wilcox that police found “no evidence of third-party involvement” and no evidence that the businessman was planning his own death.

Statements detailing how the housekeeper, driver, and personal assistant had raced to stop Jacqueline Pack boarding the plane and bring her home were also read aloud.

Her husband was born in Honolulu, Hawaii, in 1972 and made his home in Texas. He met and married his wife at school; he was a star footballer, she was a cheerleader.

Later he attended the United States Air Force Academy and he remained a patron of veterans’ charities throughout his life. He was described as a loving father to his four children, a scout camp leader who loved snowboarding, and travelling the world. He had nicknamed his family “the Six Pack.”

Wilcox delivered a conclusion of death by misadventure. She told the court she was satisfied the “incredibly talented” businessman had ended his own life, but had found insufficient evidence of intent to rule the death a suicide.

“I take into account the past history of impulsive behavior, the fact that Joshua was jet-lagged, had got exceptionally upset after an argument, was under stress from the enormous deal at work, and had been drinking,” she said.

The coroner mentioned that Pack had previously lost his brother to suicide.

An official statement from Fortress said: “Everyone at Fortress is grieving the loss of one of our most exceptional leaders. Despite our sorrow, our commitment to our investors remains unwavering.

“We know the best way to honor Josh’s legacy is to continue safeguarding our investors’ capital with the same focus and discipline that has defined Fortress for more than 25 years.”

If you are experiencing feelings of distress, or are struggling to cope, you can speak to the Samaritans, in confidence, on 116 123 (UK and ROI), email jo@samaritans.org, or visit the Samaritans website to find details of your nearest branch.

If you are based in the USA, and you or someone you know needs mental health assistance right now, call or text 988, or visit 988lifeline.org to access online chat from the 988 Suicide and Crisis Lifeline. This is a free, confidential crisis hotline that is available to everyone 24 hours a day, seven days a week. If you are in another country, you can go to www.befrienders.org to find a helpline near you.