Police from across the country arrived in Seaford to pay their respects to the fallen officer.
A wake will be held at Chapey & Sons Funeral Home in Bethpage on Thursday.
NYPD Officer Brian Moore was shot in the head while patrolling Queens.
The 40-year-old leaves behind his wife and two children.
An officer fired a single, fatal shot after the suspect allegedly lunged at him with a knife, police said.
Outraged Long Islanders took to the streets Sunday.
The diverse group of protesters stormed city streets, forcing the shut down of Broadway, the West Side Highway, Brooklyn Bridge and Holland Tunnel.