Ismaaiyl Brinsley, the killer of two NYPD officers, was a psychologically disturbed man who acted alone and had for weeks gone on anti-government and anti-police tirades on social media before he shot the officers on a Brooklyn street on Saturday, officials said Monday.

"The investigation conducted so far leads us to believe that he acted alone," Police Commissioner William Bratton said at a news conference. "Nothing in the investigation up to this point leads us to believe he was anything but a sole operator."

The killings of the police officers have generated a number of what Bratton labeled "copycat" threats to kill officers, but he emphasized that none of them have proved to be anything of significance.

As scores of NYPD detectives continue to delve into the troubled life of the suicidal Brinsley, 28, they have discovered hundreds of cellphone and social media postings that they hope will give a fuller picture of what pushed him to kill Officers Wenjian Liu, 32, and Rafael Ramos, 40.

"A lot of these things are self-despair but they are also anti-government," NYPD Chief of Detectives Robert Boyce told reporters in the briefing with Bratton and Mayor Bill de Blasio at police headquarters about Brinsley's Instagram postings.

"It is quite scary," said Boyce about the profile that was emerging of Brinsley.

On Saturday, when Brinsley broke into the apartment of his ex-girlfriend in Maryland, he actually put the gun to his own head before shooting and wounding her, but not before she talked him out of killing himself, recounted Boyce.

"We have a very disturbed young man here," Boyce added.

On Nov. 25 Brinsley posted an anti-government tirade in which he railed "quite a bit" against America and its inequities and talked about the Michael Brown and Trayvon Martin cases,Boyce said.

On his final bus trip Saturday from Maryland to New York City, Brinsley had his wounded girlfriend's cellphone and is seen on an Atlantic Center Mall video talking into it, police said. Brinsley finally hid the phone in a heating unit at the mall and it took about 100 officers to find it so that it could be analyzed, according to Boyce.

Police also recovered from Brinsley's cellphone thousands of images, including a video of a demonstration in Union Square Park around Dec. 1 in which he was a spectator, Boyce noted. The demonstration likely related to events in Ferguson, Missouri, after a grand jury refused to indict a police officer in the shooting death of Brown. On Dec. 3, a Staten Island grand jury declined to indict an NYPD officer in the death of Eric Garner.

The main effort of police now is to try and determine what Brinsley did on Saturday from 12:07 p.m. until 2:47 p.m., when he approached the two officers in their squad car and shot them to death, Boyce said. A recording was found of Brinsley walking around Atlantic Mall in Brooklyn, holding a bag with a Styrofoam container that may have held the gun used in the slayings, according to Boyce..

Boyce said cops were pushing hard to fill in the details of the missing two-hour gap in an effort to help the families of the slain officers, as well as Brinsley's parents, gain closure.

"We owe it to the families to find out what happened, that is our main concern," Boyce added.

Bratton said a test installation of new shotspotting technology actually captured the sounds of the four shots during the slaying. The NYPD has put up some acoustic shotspotting towers to help triangulate shootings in areas of Brooklyn as a prelude to a wider rollout of the devices, police said. The NYPD hopes the devices will allow cops to dispatch emergency vehicles to a shooting scene before 911 calls are made. The active towers near the shooting site actually captured the shots from Brinsley's handgun, but that evidence was moot as the officers were mortally wounded the moment the sounds were heard.

"It is one of the ironies of the events of Saturday that technology that will in the future save lives is in the process of now being installed,"Bratton said.