Peter Liang, the rookie Brooklyn cop who shot and killed unarmed black man Akai Gurley two weeks ago, was texting his union rep instead of calling for help as Gurley lay dying, the New York Daily News reports.

Gurley was walking in a dark stairway of East New York's Pink Houses public housing complex with his girlfriend Melissa Butler (above center) at the time of his death. Police sources told the Daily News officials attempted to reach Liang and his partner for over six minutes after the killing to no avail:

Right after rookie cop Peter Liang discharged a single bullet that struck Gurley, 28, he and his partner Shaun Landau were incommunicado for more than six and a half minutes, sources said Thursday.

In the critical moments after the Nov. 20 shooting, the cops' commanding officer and an emergency operator — responding to a 911 call from a neighbor and knowing the duo was in the area — tried to reach them in vain, sources said.

"That's showing negligence," said a law enforcement source of the pair's decision to text their union rep before making a radio call for help.

Authorities reportedly only learned of the shooting after a neighbor called 911.

Gurley was reportedly killed by a single bullet, after Liang drew his gun upon entering the stairwell. After the incident, NYPD Commissioner Bill Bratton told reporters Liang "had no intention of striking anyone" and may have accidentally discharged his gun, and that Gurley was a "total innocent" who "did not engage in any other activity other than trying to walk down the stairwell."

According to the Daily News, Liang and his partner weren't supposed to be doing stairway patrols—known as "verticals"—that day:

"They've done verticals before," a police source said of the two officers.

"But [Deputy Inspector Miguel Iglesias]' philosophy was, 'I want a presence on the street, in the courtyards — and if they go into the buildings they were just supposed to check out the lobby."

Another source said the commander was furious after the shooting, raging, "I told them not to do verticals."

Sources also told the News that Liang's text messages indicated he did not know the exact address of the building. Brooklyn District Attorney Ken Thompson is investigating and may present evidence to a grand jury.

Update: A spokesman for the NYPD's union denied that Liang texted a union rep in a statement to BuzzFeed News:

The Daily News story about the officer texting a union delegate does not appear to be true. We have over 400 delegates but the ones that serve the area he was working in did not receive any texts from him.

[Image via AP}