Sam Holland is the award-winning author of the Major Crimes series, following detectives as they investigate murders committed by brutal serial killers in the south of England. 
Her debut, The Echo Man, shocked and enthralled readers and reviewers alike with its sinister depiction of a serial killer copying notorious real-life murderers of the past. 
The Twenty is her second novel and is out now. It will be followed in May 24 by The Puppet Master.