With “Death Sentence,” James Wan, the director who hit the big time with the first “Saw” movie, advances from the merely grotesque to the truly reprehensible.

What’s doubly disturbing is that the morally duplicitous “Death Sentence” on some levels represents superior filmmaking. It stars the reliable Kevin Bacon as a suburban dad whose oldest son becomes the victim of a random killing by an inner city gang. The film’s opening 15 minutes, which introduces us to the Hume family and explores their grief at the loss of a child, is solid movie-making.

And then it all goes wrong.

Realizing that his child’s murderer will take a plea bargain and will serve only a few years in prison, businessman Nick Hume (Bacon) refuses to testify and allows the miscreant to go free. He’s planning a more personal form of revenge, one that involves stalking and killing the swaggering punk, who committed the crime as part of a gang initiation ceremony.

But his eye-for-an-eye vendetta backfires when the gang and its leader, Billy (Garrett Hedlund), retaliate. First they attempt to assassinate Nick as he leaves his office. Failing to kill him, they announce they’re targeting his wife (Kelly Preston) and surviving son (Jordan Garrett).

Before it’s all over, innocent blood will be shed, and Nick will have sold himself to the Dark Side.

Wan proves himself a more than competent action director. Midway through “Death Sentence” there’s a gripping chase through a multilevel parking garage that has been captured in one audacious take. And the film culminates with an extended action sequence in which the combat-inexperienced Nick somewhat improbably invades the gang’s meth-lab hideout, bent on cleaning house.

Here’s a movie that clucks its tongue at vigilantism, attempting to claim the high moral ground while delivering an atavistic fantasy guaranteed to cater to an audience’s blood lust.

Really, you can’t have it both ways.

Rated: R for strong bloody brutal violence and pervasive language. Rating: 2 stars.