Transcript for NYPD on High Alert for Wake of Slain Officer
To arrests and a wave of serious threats against police officers since two officers were killed in cold blood last weekend. One will be laid to rest tomorrow and ABC's David Wright has the story. Reporter: This morning, a disturbing trend. The NYPD is investigating some 40 cases of people threatening more violence against the police. Many of them turned out to be idle threats but there have been at least six arrests. In one case a man was overheard at the bank saying they should have killed two white cops, not an his panic and asian and said he'd kill a white cop by Christmas. At his home they recovered two guns and a set of brass knuckles. In another a suspect called the 84th precinct where the two slain officers served falsely identified himself as the gunman who killed them. The crank caller now charged with making terrorist threats. ? new yorkers continue to pay their respects here at the corner where the two officers were gunned down. On Christmas night, the Ramos family came here to pray and to thank every officer standing vigil here. This family is destroyed. Wow, it's just crazy. This is really crazy, man. Why? Why is this -- why is this happening? How do you explain this to your children? Reporter: The first of the funerals Saturday at this Brooklyn church is expected to be huge. Jetblue now offering the comp flights for men and women in blue from other parts of the country would plan to attend. Officer Ramos' funeral set to take place here tomorrow at 10:00. Vice president Biden plans to attend. Officer liu's funeral has yet to be scheduled. The NYPD apparently taking time to allow family members to get here from China.
This transcript has been automatically generated and may not be 100% accurate.