Cross Down by James Patterson & Brendan DeBois

Alex Cross is gravely injured. Only his partner and friend John Sampson can keep him safe . . . and get justice.

For the first time, John Sampson is on his own. 
 
The brilliant crime-solving duo of Washington, DC’s, Metro PD and the FBI has a proven Detective Alex Cross makes his own rules. Detective John Sampson enforces them.
 
When military-style attacks erupt, brutally sidelining Cross, Sampson is sent reeling.  The patterns are too random —Sampson’s friend, his partner, his  brother —have told him.  Don’t trust anyone . 
 
As a shadow force advances on the nation’s capital, Sampson alone must protect the Cross family, his own young daughter, and every American, including the president.