A family and colleagues are grieving after an Australian Federal Police officer took his own life at the agency's Melbourne headquarters, the second to do so in less than a year.
The man was found by his colleagues at AFP's office on La Trobe Street about 9am on Saturday.
"Our colleague's death is not believed to be suspicious," commissioner Andrew Colvin said in a statement.
"It is not possible to put into words the grief and acute impact today's loss will have on all within our close-knit AFP family."
Mr Colvin said AFP will provide whatever support they can to the officer's family and colleagues.
Victoria Police is investigating the circumstances surrounding the officer's death and will prepare a report for the coroner.
The incident comes nine months after a female AFP officer died in a non-suspicious shooting inside the same building.
Federal opposition leader Bill Shorten says he has spoken with the AFP and passed on his sympathies to the family.
"Anyone, anywhere, who's mentally unwell and doing it hard or you know someone who is, please go and get help," he told reporters at a press conference in Melbourne.
Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14.
Suicide Call Back Service 1300 659 467.
Multicultural Mental Health Australia www.mmha.org.au.
© AAP 2017