'He was the best father I could ask for': Son's heartbreaking tribute to murdered New York police officer

The son of a New York police officers who was shot dead has posted a heartbreaking Facebook message paying tribute to the "best father I could ask for".

Rafael Ramos, 40, was killed alongside Wenjian Liu while sitting in a patrol car on Saturday.

The attacker, Ismaaiyl Brinsley, had warned on social media that he planned on "putting wings on pigs," suggesting he had been motivated by the deaths of black teenagers Michael Brown and Eric Garner at the hands of police officers.

Ramos's 13-year-old son, Jaden, said it was "the worst day of my life", adding that it was "horrible that someone gets shot dead just for being a police officer".