None Shall Sleep Trilogy Series by Ellie Marney

The None Shall Sleep sequence by Ellie Marney is a trilogy of young adult crime thrillers. The series follows two teenagers, Emma Lewis and Travis Bell, who are recruited by the FBI to interview juvenile serial killers. 

Total 3 books in the series - 

• None Shall Sleep: In 1982, the FBI recruits teens Emma and Travis to interview juvenile killers. They must use the manipulative Simon Gutmunsson to help stop an active serial killer.
• Some Shall Break: Emma and Travis reunite at Quantico to hunt a copycat of the killer Emma originally survived, forcing another dangerous deal with Simon.
• All Shall Mourn: After Simon escapes, Emma and Travis lead a global manhunt from Morocco to Mexico to end his psychological games in a final showdown.