The country that executed more than four times as many convicts as the rest of the world combined last year is slowly phasing out public executions by firing squad in favor of lethal injections. Unlike the United States and Singapore, the only two other countries where death is administered by injection, China metes out capital punishment from specially equipped "death vans" that shuttle from town to town.

Makers of the death vans say the vehicles and injections are a civilized alternative to the firing squad, ending the life of the condemned more quickly, clinically and safely.

The switch from gunshots to injections is a sign that China "promotes human rights now...