Son Mourns NYPD Cop Shot Dead With Partner

— -- The son of a New York City policeman shot dead Saturday along with his partner "couldn't comprehend" what had happened to his father, Mayor Bill de Blasio said Saturday night after speaking to the boy.

Rafael Ramos, a two-year veteran of the NYPD, had celebrated his 40th birthday on Dec. 12. Police Commissioner Bill Bratton said Ramos was a school safety officer before fulfilling his lifelong dream was to be an NYPD cop.

Rosie Orengo, a friend of Ramos, said he was very involved in the church and encouraged others in their marriages.

"He was an amazing man. He was the best father and husband and friend," she said. "Our peace is knowing that he's OK, and we'll see him in heaven."

Ramos' partner Wenjian Liu, who was married two months ago, was also shot and killed today in Brooklyn. They were ambushed while sitting in an NYPD car, city officials said.

"We met the parents of Officer Liu, the woman he recently married," Mayor Bill de Blasio said. "We met the wife of Officer Ramos. We met his 13-year-old son, who couldn't comprehend what had happened to his father."

The NYPD said the man who shot and killed the two police officers is Ismaaiyl Brinsley, 28, who has a criminal history in several states.

Police believe Brinsley shot his ex-girlfriend in Baltimore earlier in the day, and then posted "anti-police postings" on her Instagram account, NYPD Commissioner William Bratton said.

Baltimore police investigating the shooting there found the posts, which included threats against New York police, and sent a message alerting the NYPD about Brinsley, but it arrived just about the time the shootings occurred, Bratton said.

"Two of New York's finest were shot and killed, with no warning, no provocation," Bratton said. "They were quite simply assassinated -- targeted for their uniform."

The Associated Press contributed to this report.