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Rapper Heavy D died today after being rushed to a Los Angeles hospital. He was 44 years old. His cause of death was not immediately known.

Heavy D was returning from a mall at around 11:30 a.m. and was climbing a set of stairs at his condominium when he experienced trouble breathing, according to staff at his Beverly Hills building.

The staff tried to help him to his home but he collapsed. When police arrived, they found him conscious but still having difficulty breathing. He was rushed to Cedars-Sinai Medical Center around noon, where he was pronounced dead.

The cause of death will be determined by the coroner’s office, but police said there was no indication of foul play.

Adam Mills, a designer who was in the building and knew Heavy D, told TMZ.com that he found him leaning against a rail in distress. Mills said the rapper told him, “I can’t breathe, I can’t breathe.”

One of Heavy D’s associates told TMZ the rapper had pneumonia, but another said he fell down the stairs. Mills told TMZ he craddled Heavy in his lap while others called 911.

Heavy D, born Dwight Arrington Myers, was one of the most influential rappers of the 1990s. He was the leader of the hip-hop trio Heavy D & the Boyz, which gained mainstream fame for the theme song for the TV show “In Living Color.” (The song was first “In Living Color,” Heavy D & the Boyz later recorded a new theme, “Cause That’s the Way You Livin’ When You’re in Living Color.”) Heavy D also rapped on Michael Jackson’s “Jam” and Janet Jackson’s “Alright.”

In recent years, Heavy D focused more on TV and movie appearances. He made a cameo in Eddie Murphy and Ben Stiller’s new film, “Tower Heist.” Heavy D performed at October’s BET Awards, his first live performance in 15 years.

In pop culture, Heavy D is also remembered for his mention in the Notorious B.I.G.’s 1994 hit single “Juicy” with the lyric “Salt’n'Pepa and Heavy D up in the limousine.”