Miami Beach police say there was no foul play involved in the death of 85-year-old photographer Bob Adelman.

Police were called to investigate after Adelman was found dead at his home March 19.

Police spokesman Ernesto Rodriguez said Tuesday that an autopsy determined that Adelman died from natural causes and an existing medical condition.

Adelman volunteered for civil rights organizations in the 1960s, and his images were published nationwide. Among his best-known subjects were the Rev. Martin Luther King Jr. delivering his "I Have a Dream" speech and a group of black youths blasted by water from a fire hose in Birmingham, Alabama.

Adelman went on to document poverty, the women's movement, the gay rights movement, public health issues and the emerging influence of pop art.