Killer of Morgan Freeman's Granddaughter Sentenced to 20 Years

The man convicted of killing Morgan Freeman's step-granddaughter is going away for 20 years ... TMZ has learned.

E'Dena Hines' killer, Lamar Davenport, was sentenced Thursday in NYC ... according to Manhattan D.A. Cyrus R. Vance, Jr.

Davenport was convicted of manslaughter last May. As we reported, he killed Hines -- who was his girlfriend at the time -- in August 2015 outside of their NYC apartment. Witnesses said he repeatedly stabbed her as he screamed about religion.

Davenport was acquitted of second-degree murder after his lawyer argued he was messed up on PCP when he attacked E'Dena. However, a judge subsequently found him guilty of first-degree manslaughter.

After he's released from prison, Davenport will be placed under post-release supervision for 5 years.