A family member told the newspaper the 45-year-old actor's death was witnessed by his brother Michael, who was across the street.
"The poor kid had a terrible accident," Jim McManus, 75, an uncle of Bobby Spillane told the Daily News. "Michael said he'll never forget the thump when he hit the ground. He said, 'That will be in my mind forever.'"
Authorities were investigating the death but it appeared to be accidental, the newspaper said.
Bobby Spillane appeared in TV shows such as "Law & Order" and movies, including "The Thomas Crown Affair."
His father was shot to death in 1977 when he was 12 years old.