New York Mayor Bill de Blasio on shooting of 2 NYPD officers: 'When police officers are murdered, it tears at the foundation of our society. This heinous attack was an attack on our entire city' - @BilldeBlasio

Attorney General Eric Holder on killing of 2 NYPD officers: 'This was an unspeakable act of barbarism... This cowardly attack underscores the dangers that are routinely faced by those who protect and serve their fellow citizens. As a nation we must not forget this as we discuss the events of the recent past... Our nation must always honor the valor - and the sacrifices - of all law enforcement officers with a steadfast commitment to keeping them safe' - statement via @ZekeJMiller

NYPD gunman is believed to have posted anti-police messages on Instagram account prior to shooting officers, police say - @NBCNewYork

NYPD received fax warning about suspect from Baltimore, Md., authorities, 'but it was too late'; suspect shot ex-girlfriend in Baltimore prior to shooting police, NYPD Commissioner says - @NBC live broadcast

NYPD officers killed in Brooklyn shooting identified as Wenjian Liu and Rafael Ramos; deceased suspect identified as Ismaaiyl Brinsley - @CBS live broadcast