Phoenix police were investigating Thursday a harrowing crime scene at a local residence after a man shot and killed four of his family members and then himself following a nasty dispute over the family business.

The unnamed victims, between ages 28 and 75, were found dead with multiple gunshot wounds in different areas of the Phoenix home on Thursday afternoon after the suspected gunman's wife escaped the carnage and called 911, The Arizona Republic reported.  

Phoenix police spokesman Trent Crump said the gunman apparently first killed his two brothers and then shot his mother when she came downstairs after hearing the first shots.

The shooter then went upstairs and killed his sister-in-law before turning the gun on himself, Crump told Reuters.

"It's very obvious that whether it was the heat of passion of the moment or the anger of what happened he certainly went to great lengths to make sure that each of them were dead."

Investigators believe the brothers were embroiled in a dispute over the family businesses, which includes a transportation company and restaurants.

During the shootings, the man's wife escaped with their 11-month-old and 3-year-old daughters through a sliding door downstairs, Crump told Reuters. Another female relative also escaped.

Authorities said they expected a standoff when they arrived at the house after the wife called 911. But by the time police entered the home, the alleged gunman was found dead in an upstairs bedroom, according to The Arizona Republic.

As of Friday afternoon, the victims' names have not been released. Investigators are reportedly working with the Moroccan consulate to notify relatives.