The bungling officers were nowhere to be seen after leaving the AR-15 on the trunk of their patrol car outside a busy hotel and shopping street on Monday night.
Shockingly, after the officers returned, they failed to notice the menacing rifle and drove off.
It was only after a woman chased the car as it drove away, that the officers realised their mistake.
Passer-by Nick Gonzales, who photographed the shocking scene above, also alerted two bike cops after seeing the rifle at around 9 pm Monday night, describing them as being 'shocked as hell'.
Doh: The Seattle Police officer left their loaded rifle unattended on a patrol car outside a busy down town area today
There is a chain of command investigation that will look into the circumstances that contributed to this incident.
'Just the fact that the rifle was left on a patrol car unattended is embarrassing, and people should expect more from the Police Department.'
According to the website, Seattle police keep rifles in three states; unloaded, patrol-car ready and tactical ready.
A full investigation has been launched.
The Police officers involved - highly trained and specially selected to carry the lethal weapons - have yet to be named.
Cathryn Olson, civilian director of the Office of Professional Accountability, said: 'The incident was brought to my attention earlier this morning, and I immediately contacted SPD Command Staff.
'I learned that Captain (Joe) Kessler, the commander of the West Precinct, had already begun an investigation into the circumstances involved.
'It is unacceptable that a rifle was left unattended on a patrol car, and people should expect more from their police department.
'We are very grateful to the two good Samaritans who alerted police to the unattended rife: Nick, the SLOG tipster who flagged down near-by SPD bicycle officers who were separately responding, and a woman who followed the patrol car and alerted the driver about the rifle.'
Read more: http://www.dailymail.co.uk/news/article-2009273/Keystone-cop-Officer-leaves-loaded-rifle-boot-patrol-car--drives-away-gun-STILL-there.html#ixzz1QlaVwmWg
I am just curious but isn't seattle where the cops punched that chick in the face for jay walking last year? They really got their shit together!