Baltimore Ravens owner Steve Bisciotti says the team DID try to obtain the Ray Rice elevator video from the Revel Hotel & Casino ... but were initially shot down ... and simply gave up.
Bisciotti just penned a letter to fans ... saying, "You deserve an explanation" -- and spells out how the team handled the Rice situation from the start.
In his letter, Bisciotti says ... "We contacted the casino management and asked if there was video of the incident from inside the elevator that we could see. The casino would not share such video."
He claims the Ravens then contacted police and prosecutors -- but were shut down then, too.
But Bisciotti says the team's hunt for the video officially ended in March -- when Ray was charged with aggravated assault.
"At this point, we decided to defer action until completion of the court proceedings. We stopped seeking to view or obtain a copy of the video. We halted our fact-finding."
Bisciotti admits ... "That was a mistake on our part."
The police had seen video from inside the elevator. The prosecutor and the judge, who had also seen such video, allowed Ray into the program that would eventually clear him of the assault charge.
The Ravens owner says the team did not see the footage from inside the elevator until Sept. 8th -- when TMZ Sports posted it -- and team honchos made a quick decision to fire Rice.
"Seeing that video changed everything. We should have seen it earlier. We should have pursued our own investigation more vigorously. We didn’t and we were wrong."
Bisciotti concludes his letter ... "I am sorry we let you down."