Innocuous phrases Alison Parker used every day to describe her job may have led to her death, simply because Vester Lee Flanagan thought they were racist.

The 24-year-old TV reporter who was shot and killed by the disgruntled ex-employee on Wednesday somehow angered him by using terms like 'swinging' by an address or going out into the 'field' while she was an intern at WDBJ.

It sheds further light on the murderer's erratic behavior, details of which have emerged since he callously gunned down Parker and cameraman Adam Ward live on breakfast TV.

Flanagan, 41, clashed repeatedly with photojournalists, belittling them in public and intimidating them with his aggressive and violent temper, before he was fired in 2013.

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Alison Parker somehow angered Vester Lee Flanagan by using terms like 'swinging' by an address or going out into the 'field' while she was an intern at WDBJ. The gunman believed they were racist and led to him filing a complaint against her in 2012

But now colleagues have revealed his assumptions were 'crazy' and even described one occasion where he believed someone bringing a watermelon in for fellow staff was a racist joke directed at him.

They were included in a complaint filed by Flanagan while Parker was working at the Roanoke, Virginia, station in 2012.

The report, seen by the New York Post, that was written by news editor Greg Baldwin read: 'One was something about 'swinging' by some place; the other was out in the 'field'.'

Parker, who was referred to by her middle name as Bailey in the documents, was never disciplined for the remarks.

But they appear to be the 'racist' comments Flanagan was referring to when he Tweeted in the aftermath of the deadly shooting.

Ryan Fuqua, a video editor at WDBJ, told The Post: 'That's how that guy's mind worked. Just crazy, left-field assumptions like that.'

'He was unstable. One time, after one of our live shots failed, he threw all his stuff down and ran into the woods for like 20 minutes.'

Trevor Fair, a 33-year-old cameraman at WDBJ, told the newspaper the words Parker used are commonplace but that they would routinely anger Flanagan.

Colleagues have revealed Flanagan's assumptions were 'crazy' and even described one occasion where he believed someone bringing a watermelon in for fellow staff was a racist joke directed at him

'We would say stuff like, "The reporter's out in the field." And he would look at us and say, "What are you saying, cotton fields? That's racist".'

'We'd be like, "What?' We all know what that means, but he took it as cotton fields, and therefore we're all racists.'

Fair added: 'This guy was a nightmare. 'Management's worst nightmare.'

On Wednesday, Daily Mail Online revealed management at WDBJ dubbed the failed newsman the 'human tape recorder' because he frequently parroted what interviewees had told him rather than doing his own journalism.

He was also censured for wearing an Obama sticker while recording a segment at a polling booth during the 2012 US Presidential Election - a clear breach of journalistic impartiality.

The complaints are outlined in court papers seen by Daily Mail Online that include a scathing performance review carried out prior to his termination in Feb 2013.

The station filed the documents to rebutt a wrongful termination claim which he had brought, claiming he was the victim of discrimination because he was black and gay. The station won the case.

Flanagan earned a dismal 1 out of 5 score in several categories for his poor communication skills and a failure to show respect to colleagues.

It sheds further light on the murderer's (left) erratic behavior that has emerged since he callously gunned down Parker (right) and cameraman Adam Ward live on breakfast TV

The veteran multimedia journalist was also criticized for missing deadlines and producing reports that were 'lean on facts' and left viewers confused.

In a sometimes-rambling account of his time at WDBJ Flanagan accused co-workers of racially harassing him by placing the watermelon around the office.

'The watermelon would appear, then disappear, then appear and disappear, then appear and disappear again only to appear again,' he wrote in a May 2014 letter to presiding Judge Francis Burkart.

'This was not an innocent incident. The watermelon was placed in a strategic location.'

In his hate-filled manifesto that surfaced on Wednesday, Flanagan spoke of how his anger at perceived racial slights he had suffered, along with the Charleston church shootings, had forced him to kill the animals.

According to an unnamed source, when police raided his bare, colorless apartment after yesterday's horror unfolded the found the door smeared with cat feces and the carpets inside soaked in their urine, though there is no evidence of this in these images.

According to neighbors, Flanagan was often seen throwing their feces from the balcony.

Elsewhere in the apartment officers are said to have found a collection of sex toys with 'human material' on them, though they were presumably removed before these images were taken.

Flanagan grew up in Oakland, California, where he attended high school, but appears to have largely cut ties with the West Coast several years ago after moving to Virginia.

There are no images of family or friends around his apartment, and when Mail Online spoke to his relatives today, they seemed not to know much about Flanagan's life in recent years.

Guynell Flanagan, the killer's cousin, said the last time she had seen Vester was in 2013 when he visited for Thanksgiving dinner.

A former prom date of Flanagan's from high school also said that none of his former friends had known he moved east, or that he was going under the name Bryce Williams.