'Don't worry. I'll talk to you later.' But Hinsdale man was never heard from again on 9/11.

Robert Rasmussen called his wife at their home in Hinsdale from the 79th floor of the World Trade Center south tower shortly after a plane struck the north tower on the morning of Sept. 11, 2001.

In a voicemail, he tells Anna not to worry.

"Just calling to let you know I'm in one piece, standing in 2 World Trade," he said in the message his wife shared with CBS 2 Chicago nearly a decade later. "Don't worry. I'll talk to you later."

The 42-year-old financial analyst and father of three young children was never heard from again.

Rasmussen's remains were never recovered from the rubble of the collapsed towers. His obituary notes that he was identified from a photograph by a survivor of the attacks on the twin towers who told authorities Rasmussen was last seen on the 78th floor of Tower 2 just 45 seconds before the impact of the second plane.

The North Dakota native had moved to New York in 1989, then to Hinsdale when his company transferred him to a Chicago branch in 1999.

In pictures, his wide smile takes up much of his visage and his eyes shine through glasses.

Just 7, 2 and 1 at the time of their father's death, his three children - daughter Taylor is the oldest, followed by son Jack and youngest son Sam - all share some of their father's features now that they're in their 20s.

Rasmussen's oldest children pursued careers in the arts, while the youngest is in marketing.

His widow, who spoke with reporters after the death of 9/11 financier Osama bin Laden in 2011, said she is reminded of her late husband often.

"It's hard not having Bob with us, but we had a lot of tender family moments," she told the Chicago Tribune a decade ago.