WDBJ released a statement on Vester Flanagan's employment history with the station. 
Flanagan fatally shot a reporter and cameraman on August 26. 
Below is WDBJ's statement.

Vester Flanagan was employed by WDBJ7 as a reporter between March 2012 and February 2013.Flanagan applied for the position using the air name of Bryce Williams. As part of WDBJ's standard protocol his background check resulted in positive references.
Flanagan’s job performance and his interaction with his co-workers led his manager to place Flanagan on a succession of performance improvement plans. Only slight improvement was noted each time.
Flanagan was placed on a final warning in December 2012 for failure to check his facts in a news story and, generally, for poor news judgment.
In January 2013 he accused a photographer of making trouble for him by questioning a decision to go on private property in pursuit of a story. At that point, he raised some concerns with HR of perceived unfairness, which were immediately investigated and found to be without merit.
Shortly after that, he confronted an anchor who was assigned to review one of his scripts.
At that point, management made the determination that he needed to be separated from the company.
On February 1, two news managers and the HR business partner notified Flanagan of the decision to terminate his employment. He reacted angrily, telling them that they would have to call the police because he was going to “make a stink and it was going to be in the headlines.”
The HR rep called 911. Employees had been notified to give Flanagan space to clean out his desk. At his desk, Flanagan attempted to reach the corporate CEO, without success. At that point, police arrive and escorted him from the building. On the way out, he handed a wooden cross to the news director and said, “You’ll need this.” He also made a derogatory comment to Adam Ward as he left.
The only contact between WDBJ7 and Flanagan after that were routine calls to HR about termination benefits.
Shortly thereafter, Flanagan filed a complaint of harassment and discrimination with the Equal Employment Opportunity Commission. WDBJ7 responded that his claims of mistreatment were unfounded and the EEOC denied the claim. He later filed a civil action in local court in Roanoke. That action was dismissed.
In two and half years since the termination, WDBJ7 employees reported seeing Flanagan in public places and there were no confrontations. He was never seen following employees and he did not attempt to enter the offices of WDBJ7.
All claims of mistreatment were investigated by senior management, by the HR representative and legal counsel. All investigations determined that no reasonable person would have taken any of the cited instances as discrimination or harassment.