"It was a possible accident or else he died of natural causes," Winter said.
Busby was named Motown's president and chief executive officer in 1988 and stayed there for seven years. During that time he oversaw such then up-and-coming artists such as Boyz II Men and Queen Latifah.
Singer Smokey Robinson said he was saddened by Busby's death.
"I had tremendous respect for the way he continued the Motown legacy ... My condolences to his family at this difficult time," Robinson said in a statement.
Born in Los Angeles, Busby started his music career at Memphis-based Stax Records.
Busby bounced around several record companies during the 1980s doing promotional work. He was named as vice president of the black music division of MCA Records in 1984. He was later promoted to president of the division.
After his Motown tenure, Busby was the head of the urban division at DreamWorks Records between 1998 and 2001. He later worked at Def Soul Classics, a division of Def Jam Records.
Busby also was a major shareholder in the nation's first black-owned national bank, Founders National Bank of Los Angeles, along with Magic Johnson and Janet Jackson.
