The Boyfriend

Jack Till, who has retired from the LAPD after a respected career as a
homicide detective, now works as a private investigator, comfortable
chasing down routine cases while visiting his 24-year-old daughter,
Holly, who has Down Syndrome. But when the parents of a recently
murdered young girl, about Holly's age, ask for his help when the police
come up empty, Till reluctantly takes the case.

It was
discovered after her death that the victim had been working as a
high-class prostitute, and the police are content to assume she was
killed by a client, common in such a dangerous line of work. Yet as Till
digs deeper, he realizes that the victim is just one of several young
female escorts killed in different cities in the exact same way—all
had strawberry blonde hair, and all were shot with a 9mm handgun in the
sanctity of their apartments.

Till must find his way around the
tawdry and secretive online escort business, and decode ads placed by
young women who all use false names, sometimes advertise using other
women's pictures, and move from city to city every few months. Yet when
Till is finally able to catch up with the killer, he finds that the man
he's after is far more dangerous and volatile than he ever could have
imagined. As the body count rises, Till must risk his life to find this
seductive and ruthless killer whose murderous spree masks a far deadlier
agenda.