Susan Candiotti's documentary, "Downward Spiral: Inside the Case Against Aaron Hernandez," airs on CNN at 9 p.m. ET Tuesday.
(CNN) -- Why would former New England Patriot Aaron Hernandez allegedly "orchestrate the execution" of Odin Lloyd, leaving him shot seven times and his body near a construction pile in an industrial park?
The motive was something trivial, according to a source with knowledge of the investigation.
Investigators believe Hernandez' s simmering anger over two incidents at a nightclub and his apartment led him to allegedly kill Lloyd two nights later, CNN has learned.
Hernandez "drove the victim to the remote spot, and then he orchestrated his execution," Assistant District Attorney Bill McCauley said last year.
One of the incidents involved Lloyd seeing guns and ammunition stored at Hernandez' so-called flop house, his apartment in Franklin, Massachusetts. The other thing that set off Hernandez was a conversation Lloyd had with two men at a club earlier that night, June 14, 2013, a source tells CNN.
The cumulative effect apparently reached a breaking point for reasons that most people would find inconsequential. The source would not say what that was, but compared it to something as insignificant as a spilled drink that allegedly led to the 2012 Boston double murder of Safiro Furtado and Daniel Abreu, a separate case in which Hernandez also has pleaded not guilty.
Lloyd's killing did not involve possible knowledge of that double murder as investigators previously considered, the source added.
Hernandez's anger was fueled by paranoia brought on, in part, by his alleged drug use including angel dust and marijuana, the source said.
The motive was hinted at in court this week, when new details emerged about the events at Rumor nightclub where Hernandez and some friends partied before moving to Hernandez' apartment about 10 miles from his home. Lloyd, a semi-pro football player and Hernandez were dating sisters.
Prosecutors say Hernandez appeared upset at the club. They describe him appearing agitated on security video. Witnesses describe him with his arms waving in the air and a parking valet saw the football player put a gun in his waistband when he got into his vehicle, according to authorities.
"An incident had occurred that caused him to arm himself," McCauley told a judge.
Hernandez' s lawyer told a judge that his client's friends said the incident at the club was not a problem.
When Hernandez and Lloyd left, they went to the tight end's apartment accompanied by two women to party, prosecutors say.
Whatever happened involving the guns and bullets at the apartment and earlier at the nightclub, Lloyd didn't think it was a big deal, according to friends who saw him the following two days leading up to his death. They said he only talked about having a good time with Hernandez.
"There's certainly a lot of what I would call smoke," defense attorney Jamie Sultan said in court. "There's no doubt about it ... But that's not probable cause that he committed murder. And you can't just throw a bunch of stuff against the wall and say that's good enough."
The fallen Patriot's alleged behavior, as described by investigators, appears to follow a bizarre pattern that has resulted in three murder charges, and a lawsuit accusing him of shooting a friend in the face and leaving him for dead.
In each case, authorities say, the violence was preceded by something perceived as disrespect or betrayal.
In July 2012, Hernandez is charged with fatally shooting two men in a car after one of them, a stranger, bumped into Hernandez on the dance floor at a night club, causing the athlete to spill his drink, according to Boston's district attorney. Hernandez felt he was being "tested," a friend is quoted as telling investigators, prompting Hernandez to follow the men out of the club and kill them in a drive by shooting.
That same friend identified in court papers as Alexander Bradley is now suing Hernandez for allegedly shooting him in the face and leaving him for dead in an industrial park in south Florida in February 2013. Prosecutors say Hernandez felt 'disrespected' by Bradley because he challenged him after the football player refused to return to a strip club to retrieve Bradley's cellphone.
In court, prosecutor McCauley said according to Bradley, trust was a big deal to Hernandez. "The more he got to know you ... the more suspicious he was," McCauley told the judge. "He was concerned (about) the things that you knew about him ... Odin Lloyd knew such things about the defendant."
Four months later, in June, 2013, Lloyd was picked up in a car said to be driven by Hernandez with two of his associates, taken to an industrial park, shot and killed, according to prosecutors. Those associates, Ernest Wallace and Carlos Ortiz, are also charged with first-degree murder and like Hernandez, have pleaded not guilty.
His lawyers this week filed a motion asking a court to authorize a subpoena demanding Hernandez's work and medical records from the New England Patriots, including records that "may bear upon (Hernandez') mental state at the time ... of Lloyd's murder."
Legal experts say the motion indicates the defense may be leaning toward arguing Hernandez suffers from diminished capacity, a legal term for someone who is less responsible for committing a crime because it's harder for them to know the difference between right and wrong.
CNN's Michelle Rozsa contributed to this report