Night Watch by David C. Taylor

Michael Cassidy is a cop in New York in the 1950's.  He's used to the usual crime victims but finding a dead jew vendor in the park is not a usual crime.  Trying to solve that takes him down some dark roads...

Severn House and Net Galley let me read this book for review (thank you). It will be published May 1st.

Finding people who knew him wasn't easy.  He kept a low profile.  But he also had a mission.  His wife and child had been killed by the Nazis and he keeps his eye out for any German he might recognize.  That resulted in the vendor's death.

Then Cassidy finds out that some of the German scientists were granted entry to the US even if they were Nazis as long as they would work for the government here.  As he begins tying pieces together, it gets even more dangerous for him.  He has someone trying to kill him.  But they want to scare him first.

In the meantime, they have had a couple of deaths of men who were killed by a drug that was administered to them.  The police department is trying to identify it but nothing is happening fast.

Cassidy is grabbed off the street and given a shot that lets him experience what they got.  It's not pleasant.  He survives but now he wants to take them down more than ever.  The problem is that they are working for the CIA...

There's plenty of political pressure, a killer after him, and he and his girlfriend  are splitting up.  You're not sure if he's going to survive or not.

It'll keep you reading.