The Visitor by Lee Child

Two female army high-flyers. Both acquainted with Jack Reacher. Both forced to resign from the service.

Now they're both dead.

Found in their own homes, naked, in a bath full of paint. Apparent victims of an army man. A loner, a smart guy with a score to settle.

A ruthless vigilante. A man just like Jack Reacher.

Although the Jack Reacher novels can be read in any order, The Visitor is 4th in the series.