An ex-TV journalist who shot dead two ex-colleagues live on air in Virginia had been ordered to seek medical help by his bosses,memos reveal.
Internal memos from Dan Dennison, then news chief of WDBJ7, show concerns about Vester Flanagan's "aggressive" behaviour towards colleagues.
They indicate the station tried to help him before firing him in February 2013.
Flanagan shot dead Alison Parker and Adam Ward at a shopping centre in Moneta on Wednesday.
He filmed the attack and posted it on social media. ABC News also said it had received a rambling fax from the 41-year-old describing himself as a "human powder keg".
The White House said Wednesday's attack showed the need for better gun control.
Flanagan was hired by WDBJ7, in Roanoke, Virginia, in March 2012 and was known on air by his professional name, Bryce Williams.
Within a few weeks, colleagues were complaining of "feeling threatened or uncomfortable" while working with him.
The memos highlight "heated confrontations" with camera operators and producers in front of guests while out covering stories.
By July 2012, Mr Dennison was requiring him to contact the Health Advocate, the employee assistance programme, or face being sacked.
"We can no longer afford to have you engage in behaviours that constitute creation of a hostile work environment," he said.