Martial Eagle feeding on adult Impala - killer or scavenger?

Recently we came across a Martial Eagle feeding on a dead adult female Impala in the Kruger National Park. The questions was - did the eagle kill it, or was it just scavenging from a fresh carcass? Given the size of the Impala and the proximity to the road, we decided it was probably scavenging from a road kill, Martial Eagles are known to scavenge on occasion. What a great sighting!