People leave items at a memorial near Tompkins Ave and Myrtle Ave December 21, 2014 in New York near the site where two New York City police officers were shot and killed. New York was reeling Sunday after the murder of two uniformed cops by a man who said he was seeking revenge for the recent killings of unarmed black men by police. The two officers, Wenjian Liu, 32, Rafael Ramos, 40, were shot in the head through the window of their patrol car in broad daylight in Brooklyn on December 20, in an attack that shocked America's biggest city just days before Christmas. Police named the shooter as 28-year-old Ismaaiyl Brinsley, allegedly a member of the "Black Guerrilla Family" gang. He fled to a nearby subway station after the attack, where he shot himself in the head on the platform. AFP PHOTO/DON EMMERT (Photo credit should read DON EMMERT/AFP/Getty Images) People leave items at a memorial near Tompkins Ave. and Myrtle Ave. on Dec. 21, 2014 in New York near the site where two New York City police officers were shot and killed. (credit: DON EMMERT/AFP/Getty Images)

WASHINGTON (CBSDC/AP) — The NAACP is calling for gun control measures following the shooting deaths of two New York police officers.

New York Police Department Officers Rafael Ramos and Wenjian Liu were shot and killed by 28-year-old Ismaaiyl Brinsley Saturday afternoon in Brooklyn. Brinsley had vowed in an Instagram post to put “wings on pigs” as retaliation for the deaths of Michael Brown and Eric Garner at the hands of white police.

“These two killings and the life-threatening injury, like so many other unfortunate incidences of gun violence, provide a stark example of the need for sensible gun control measures, and the need to thoughtfully address untreated mental illness,” the NAACP Legal Defense Fund said in a statement.

The NAACP cautioned against linking these murders to the nationwide protests over the deaths of Brown and Garner.

“While some may suggest a causal link between these killings and the recent protests and activism focused on the serious issue of police violence against unarmed African-Americans, we caution against escalating an already tense national state through rumor and conjecture,” the statement read. “Whatever motivation lay in the apparently troubled mind of the now deceased shooter of these officers, there is no connection between the peaceful protests of thousands of people of all races all over the country, and, indeed, around the world, and this hideous act of violence.”

Investigators are trying to determine if Brinsley had taken part in any protests over the deaths of Brown and Garner, whose names he invoked in his online threat, or simply latched onto the cause for the final act in a violent rampage.

At a news conference in New York on Sunday, Chief of Detectives Robert Boyce detailed Brinsley’s long criminal record, hatred for police and the government and apparent history of mental instability that included an attempt to hang himself a year ago.

Brinsley had at least 19 arrests in Georgia and Ohio, spent two years in prison for gun possession and had a troubled childhood so violent that his mother was afraid of him, police said. He ranted online about authority figures and expressed “self-despair and anger at himself and where his life was,” Boyce said.

Hours before shooting the officers, Brinsley had shot and wounded his ex-girlfriend, Shaneka Thompson, at her home in Baltimore.

“He shot me! I don’t want to die. I don’t want to die,” Thompson screamed, according to neighbor Yevette Seay. She told The Associated Press she called 911 as Thompson lay on the floor, clutching her stomach. Authorities have said Thompson is expected to survive.

After leaving Baltimore, authorities said, Brinsley took a bus north to New York City and used Thompson’s phone to write on Instagram: “They take 1 of ours, let’s take 2 of theirs.” He ended the post with references to the Brown and Garner cases.

Once in New York and shortly before he opened fire on the officers, Brinsley walked up to people on the street and asked them to follow him on Instagram, then told them, “Watch what I’m going to do,” Boyce said. Then Brinsley approached the squad car and fired four shots, killing the policemen. He ran into the subway station and committed suicide.

The shootings also deepened acrimony between rank-and-file police and Mayor Bill de Blasio. Their union president recently suggested officers sign a petition telling the mayor not to attend their funerals if they died on duty, and some officers turned their backs on de Blasio Saturday as he walked through the hospital where Liu and Ramos had been taken.

Police Commissioner William Bratton said Monday on NBC’s “Today” show that he didn’t consider that gesture appropriate, “but it’s reflective of the anger of some” police officers. The mayor has lost some officers’ confidence, Bratton said, but he suggested that recent pension changes and ongoing contract negotiations also had contributed to the uneasy atmosphere.

One of Ramos’ relatives said the family would welcome a visit from the mayor, who visited both officers’ families at the hospital Saturday but did not see them Sunday.

“If he wants to come and show support, by all means, we’ll accept that,” said Ramos’ cousin Ronnie Gonzalez.

Ramos’ 13-year-old son, Jaden, said in a Facebook post that Saturday was the worst day of his life.

“Today I had to say bye to my father,” Jaden wrote. “He was the best father I could ask for. It’s horrible that someone gets shot dead just for being a police officer. Everyone says they hate cops but they are the people that they call for help.”

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