BOSTON – They were once best friends, confidants and keepers of the most wicked of secrets.

“Inseparable,” Aaron Hernandez once described his relationship with Alexander Bradley.

They were very much separated, however, Monday on the ninth floor of Suffolk Superior Court during Hernandez’s double murder trial.

Separated by six court officers, either directly between them or ready to restrain. Separated by the distance between the witness stand (Bradley) and the defense table (Hernandez), although under different circumstances those positions could have been reversed. Separated because their relationship is as complex as it is combustible, most apparent perhaps when Bradley explained to the jury why he didn’t go to the police even after Hernandez allegedly pointed a gun between his eyebrows, fired and left him to die in an alley of an industrial area of South Florida.

Bradley survived with one eye but all his vengeance. Talking to the cops didn’t just violate his no-snitching street ethos, it violated any sense of fairness.

“I didn’t want to talk to the police,” Bradley said. “I wanted Mr. Hernandez. I wanted his life.”

The tone chilled an already tense courtroom as Bradley stared with his left eye, the one that still worked, directly at Hernandez. He tilted his head to the right and shook it in fury at his old friend. These were no empty words, no posing. Given the chance, Bradley would almost certainly kill Hernandez. And vice versa, at least if Hernandez learned that when it comes to Alexander Bradley, it takes more than one close-range shot to the skull to finish him.

Judge Jeffrey Locke broke for lunch right then, leaving Bradley’s words and stare to hang over a jury stuck contemplating the levels of personal betrayal overwhelming this case. As court officers ushered Bradley out, he walked past Hernandez, the two of them locked in a shared look of pure menace.

*****

Hernandez is charged with killing Daniel de Abreu and Safiro Furtado in a 2012 drive-by shooting after a brief encounter earlier at a Boston nightclub. Bradley is the state’s star witness, the driver of the vehicle Hernandez was in that night and the lone eyewitness capable of putting the gun in the former New England Patriot’s hand.

Across a lengthy day of direct examination (the defense’s ferocious cross of Bradley is expected to begin Tuesday) the trial focused on the chaotic friendship of Bradley and Hernandez – the former a Connecticut drug trafficker, the latter an NFL star, both of them with a propensity for rage and unnecessary violence that have dominated and doomed their lives thus far.

Hernandez, 27, is serving a life sentence for the 2013 murder of Odin Lloyd in North Attleboro, Mass. Bradley, 34, is currently doing a five-year stint in Connecticut for indiscriminately shooting up a Hartford nightclub in 2013 after someone there shot him three times in the leg over a dispute about money.

Together they make a pathetic pairing. Penned up and battle-scarred, each trying to save whatever is left of himself by accusing the other of actually killing de Abreu and Furtado.

Their relationship had begun through commerce, a buyer and a seller, Bradley often supplying marijuana on a payment plan because Hernandez was still just a college football player then, a Florida Gator, and money was tight. It wouldn’t be for long, though, not with the NFL beckoning.

They became friends. They smoked a lot. They played video games a lot. They partied a lot together. They also provided something for each other. Hernandez allowed Bradley into his orbit of superstardom. Bradley gave Hernandez undeniable street toughness that he always coveted. Bradley was true gangster. He was also the rare peer who didn’t need his money.

They also shared an unexpected level of depth. Hernandez, for all his tough-guy posturing, grew up in a two-parent, middle-class home, and had the gift of a chameleon. He went to college for three years. He could act like a thug, but he was smart and well spoken. So, too, was Bradley, who from the witness stand offered a large vocabulary. In his testimony, a car was a “vehicle,” a house was a “residence” and a gun was a “firearm.” Aaron Hernandez was “Mr. Hernandez.” He used legal jargon. Notes of his entered into evidence displayed admirable penmanship.

At one point he described issuing Hernandez a death threat this way: “I expressed my feeling to him about how I wanted to handle the situation,” Bradley said.

That’s one way to put it.

*****

Bonded by evenings of bottles and blunts, it was a rare day they didn’t at least check in by phone, and a rare week they weren’t hanging out two or three times, often in Boston nightclubs.

The most fateful came in July 2012, when Bradley testified that Hernandez grew angry that de Abreu didn’t pay him enough respect when he bumped into the Patriot and caused a drink to splash. Later, Hernandez spotted de Abreu’s party driving away at closing time and ordered Bradley to follow in pursuit.

Bradley did just that, running a red light to pull up alongside the Cape Verdean immigrant’s car. That’s when Bradley said Hernandez, wearing rosary beads as a necklace, fired five shots. He would have done more, but he was out of ammo.

The two fled and headed back to Connecticut, each of them, according to Bradley, shocked at what had occurred.

“He was kind of panicked,” Bradley said. “He said, ‘I hit one in the head and one in the chest.’

“It wasn’t a bragging tone.”

A plan was quickly enacted – stash the car and shut the hell up.

Hernandez spent time combing through news reports. Bradley returned to dealing marijuana, up to 30 pounds a week. Soon Patriots camp beckoned, Hernandez signed a $40 million contract and played an entire season for the Pats, even as, according to Bradley, he became convinced he was being followed by detectives. Hernandez also reveled in his crime, though, according to Bradley, bestowing upon himself a new nickname: “Double A.”

“It was a direct correlation to the double homicide,” Bradley said.

Back in Boston, baffled detectives had no leads and no reason to suspect a New England Patriot in the crime. These two had seemingly got away with it. They grew even closer.

*****

Then came a trip to Florida in February 2013, a haphazardly planned vacation that spoke to their general dysfunction. They went to the airport but arrived so late they left their luggage in the car and traveled with just what they were wearing despite a plan to stay nearly a week before heading to Arizona. They tried to save money by staying at the West Palm Beach La Quinta Inn (“near the Hooters,” Bradley said), yet blew $10,000 one night at Tootsie’s Cabaret.

They were stoned most of the time and drunk seemingly the rest. On one of their visits to Tootsie’s, which bills itself as “the Largest and Best Strip Club in America,” Hernandez became convinced that two fellow patrons were actually undercover cops following him.

“I said, ‘If they are, it’s because of the stupid [expletive] you did in Boston,’ ” Bradley testified. “He became standoffish. He became upset.”

The next night and another trip to Tootsie’s. By 5 in the morning, there was an argument over how to split up the sizeable bill from a private room. Then on the ride home, Bradley realized he’d forgotten his cell phone at the club, but Hernandez wouldn’t allow the car to be turned around (there were two other friends with them).

They argued, then Bradley said he fell asleep, only to awaken when the car stopped down an alley near a John Deere dealership.

“I woke up with Mr. Hernandez pointing a gun at my face,” Bradley said. “… Right between my eyebrows.”

Hernandez fired. Bradley said his ears were ringing, blood was flowing everywhere and his right eye was finished, yet he somehow maintained consciousness. He said Hernandez and another guy pushed/pulled him out of the car and left him to die. He pulled himself up on a nearby fence, started walking and then was discovered by some workers from John Deere. They called an ambulance.

At that moment Bradley had two goals.

Live. Kill Hernandez.

*****

A homicide detective from the Palm Beach County Sheriff’s Department showed up at the St. Mary’s Medical Center intensive care unit because Alexander Bradley was not expected to survive and, in a twist, maybe a homicide victim could grant an interview before he became a homicide victim. Only it was immediately clear that Bradley was going to survive and he wasn’t going to tell the cops anything.

“I have no information for you sir, with all due respect,” Bradley is heard saying during the taped interview.

Who shot you, the detective asked.

“He’s a [expletive] [expletive] who did it,” Bradley said without naming a name.

“Well, obviously, you have a big-ass hole in your head,” the detective said.

After the cop left, Bradley borrowed a phone and called Hernandez, who answered and, according to Bradley, was stunned to hear the voice of a presumed dead man.

“He said, ‘Who’s this?’ ” Bradley testified. “I said, ‘You know who this is.’ He was shocked. He definitely didn’t think I would survive.”

Hernandez proceeded to hang up. Future phone calls didn’t go much better. In text messages, Hernandez denied knowing anything about anything. Three surgeries and one prosthetic eye later, Bradley recovered and returned to Connecticut, where he began trying to lure Hernandez into a meeting so he could murder him.

“To make it even,” Bradley said.

By late March he was also trying to wring money out of Hernandez, to compensate for the pain and suffering. Maybe that would have sufficed. Maybe Bradley would have killed him anyway, just with a lot of cash to boot. Bradley kept boasting in text messages about his gun arsenal and crew of six who would ride with him and all sorts of other potential mayhem he could unleash.

Hernandez kept avoiding Bradley and ignoring most of the texts but it was clear the pressure was everywhere as spring turned to summer.

Hernandez would have continued reason to fear the police busting him for whatever involvement he had in the de Abreu and Furtado murders – Hernandez’s defense claims that Bradley was the actual triggerman. Even if that was true, Hernandez’s mere presence at, and failure to report, a double homicide would lead to criminal charges and an end to his NFL career. He would also worry that Bradley could file a civil suit, which would likewise cause massive professional harm. Or Bradley could just hunt him down.

By the start of Patriots training camp in late July, his daily whereabouts would be obvious and would make him an easy target.

Then Hernandez killed Odin Lloyd on June 13, 2013, and was arrested a little over a week later. He hasn’t had a breath of free air since. The murder of Lloyd possibly spared Hernandez’s own murder, saving his life, even if that life is one of incarceration without the possibility of parole.

Soon Boston police were piecing together the cold case of the 2012 double homicide. Hernandez’s presence at the Cure nightclub was no longer a curiosity but a lead. When the SUV they had been searching for was discovered at a Bristol, Conn., home connected with Hernandez, charges were filed.

They sought Bradley and arrested him on a restraining order violation. With no other way to enact revenge on his old pal, he broke his code and ratted to the cops, delivering a lengthy statement about what happened that night in the South End. At the time, he hadn’t been granted immunity – although that would come soon. He’ll face no charges in this case.

By the winter, though, he was locked up himself, for shooting up a bar in Hartford. It followed a 2006 conviction on dealing drugs and an unresolved arrest for assault with a firearm in Bridgeport, Conn. That is him. He’s no hero here. Had he turned Hernandez in after the double homicide, or his own shooting, he could have saved Lloyd’s life.

Bradley has served over three years of his five-year sentence and claims he is now a different person, eager to get out and be a good father for his three children. Perhaps he means it. Hernandez will have no such chance at redemption, his daughter will grow up without him around.

On Monday, though, Bradley looked no less angry, no less vengeful and no less capable of extreme violence. For all his poise and relative polish, it was too much to just sit and stare at Aaron Hernandez, the man, he said, who blasted him in the face and tried to kill him, the man who doubted his loyalty. At times, Bradley grew so upset, the right side of his face twitched.

From the stand, Bradley was trying to recount how he once wanted his old buddy dead. He sure looked like he still wished he could make it so.