A US courtroom has heard chilling testimony alleging how a lottery millionaire walked up to Australian real estate developer Greg McNicol, shot him at close range with a pistol, and then left him to die.

Freddie Young, a 63-year-old postal worker who was part of a 13-member syndicate that won $US29 million ($28.2 million) in a lottery last February, faces life in prison if convicted.

"He got out of the car, shot Greg and sped off," Thomas Benton, 18, told a jury on the opening day of the murder trial in Detroit.

"He was like 'shoot first and no questions'."

Mr McNicol, 45, was raised on Victoria's Mornington Peninsula and in 1998 moved to the US, where he used his experience as a building inspector and project manager to snap up investment properties in recession-hit areas of the US, including Detroit and Toledo.

His wife Katie told the court how he was particularly pleased with the purchase a year ago of a 10-apartment complex on Detroit's east side.

He paid just $US35,000 for the dilapidated, rat-infested property and personally set about renovating each unit.

One of the tenants was Ayana Young, daughter of the accused.

Mr McNicol's property manager, Karen James, said Ms Young had some "domestic issues", was behind on her rent, and had been given a 30-day eviction notice.

Ms James said that about two weeks before Young allegedly shot Mr McNicol, they spoke on the phone.

"He said he did not want his daughter disrespected," Ms James told the court.

On the afternoon of May 7 last year Ms James said a tenant called her and was "frantic" because Mr McNicol was embroiled in arguments and "people were calling people".

When she arrived at the apartment block, she found Mr McNicol lifeless on the ground outside the building.

Mr Benton told the court how tenants were preparing to have a barbecue with Mr McNicol, who he called "a peaceful man".

However, Ms Young pulled up in a vehicle and confronted Mr McNicol, who had a cigarette in his hand.

"She slapped the cigarette and slapped him in the face," Mr Benton said.

"He kept politely asking her to leave his property."

'Kind of disrespectful'

Under cross-examination, Mr Benton conceded Mr McNicol did become agitated and "was kind of disrespectful" to Ms Young.

A short time later her father drove up, left his car, and fired what authorities allege was the one fatal shot into the left side of Mr McNicol's pelvic area.

Wayne County prosecutor Steven Kaplan said a tape of a 911 call Mr McNicol made in the final seconds of his life will be played to the jury.

"Greg McNicol calls 911," Mr Kaplan said.

"He says 'I was shot by my tenant's father'."

The prosecutor said Young "wasn't happy with the way his daughter was being treated" and reacted by shooting Mr McNicol dead.

"It is a simple case," Mr Kaplan said.

"We know who did it: Freddie Young. It is not a whodunnit case."

Defence team

Young, who pocketed about $US1.57 million after his winning syndicate opted to take a $US29 million cash option instead of $US46.5 million annuity, was dressed in a grey pinstriped suit and sat quietly in the courtroom.

He is being represented by three of Detroit's top lawyers.

One of the lawyers, Larry Polk, said his client was a "hardworking man" who was licensed to carry a concealed pistol.

"It's not just a simple case," Mr Polk said in his opening address.

"Witnesses will not provide truthful evidence of what happened on that day."

Ms McNicol wept on the witness stand as she told how she was in her native Brazil visiting her mother on Mother's Day when she received the shocking call that her husband was dead.

She has vowed to keep working on her husband's residential projects to "continue his dream".

Ms McNicol has also filed a wrongful death civil lawsuit against Young.

The trial continues.

AAP