It was May 2010. NBC’s Law & Order was eying a place in the history books with a 21st-season pickup, which would’ve broken law_and_order_s20a tie with Gunsmoke and make L&O the longest-running drama series ever. The mothership series also had just spawned a third spinoff series, L&O: Los Angeles, which had been ordered to series. Then, just days before NBC’s upfront presentation, the network abruptly canceled the long-running show.

Fast-forward five years. It is May, and we have another veteran crime procedural that has created a mega-successful franchise, CBSCSI, facing an uncertain fate just as it launched a third spinoff series, CSI: Cyber. I hear CBS is considering different options to give CSI a final chapter next season, including a short run — as short as six episodes — but it is not a sure thing.

L&O had long finished production on its 20th season when the shock cancellation came. With public assurances from NBC and a rumored verbal agreement for a 16-episode 21st season reached that March, the 20th-season finale was not conceived as a last episode, leaving fans with no series ending.

Seeing RedThe same goes for CSI, where Elisabeth Shue’s character Julie spent the Season 15 closer in a coma, with her fate left hanging in the balance. At least for L&O the cancellation call came before the final three episodes had aired, giving fans an opportunity to savor them knowing they are the last. With CSI, viewers won’t have that option as the show wrapped its 18-episode 15th season in February with little fanfare.

The alarm bells went off in October when the current 15th season of CSI was trimmed to 18 episodes, the first time the crime drama has produced fewer than a full-season 22 episodes outside of the writers strike-impacted 2007-08 season. Then the network and producing studio CBS TV Studios did not move in to secure an early renewal with star Ted Denson, whose contract is up at the end of this season — all signs how much up in the air CSI‘s fate is.

CSI Cyber Patricia ArquetteMaking things even more complicated is the uncertain future of CSI: Cyber. With a solid cast led by new Oscar winner Patricia Arquette and timely subject matter, cyber crime, the latest CSI offshoot seemed like a slam-dunk but has done only so-so in the ratings. Still, being part of the blockbuster CSI franchise is making the show a lucrative international seller for the company.

Which brings us back to the mothership 200o series, which started it all, ranking five times as the most watched drama series in the world and spawning a billion-dollar franchise for CBS. The network alcaruso1ready pretty unceremoniously cancelled its two successful spinoffs, CSI: Miami and CSI: NY. For Miami, which also has been named the most popular drama in the world twice, it was a similar final-season air pattern — airing the season finale in April and finding out the show had been cancelled in May. (CSI: NY finished its final season in February.) The producers may have had the right idea — that last Miami episode did feature a send-off, of sorts: Most of the core ensemble (except for Emily Procter) were gathered in a bar at the end. Still, the only way the series could say goodbye to its fans after 10 seasons was through a sad tweet from star David Caruso, picture on left.

CBS can avoid that with the mothership series, especially given the fact that, with its unfinished business, the last aired episode felt nothing like a finale the show deserves after 15 years and three spinoffs, creating a Thursday stronghold for the network at a time when NBC was dominating the night and delivering a financial windfall for the studio.

I hear the actors are willing to come back for a send-off run. For CBS, bubble show renewal decisions usually come down to the scheduling meetings in the final days leading to the network’s Wednesday presentation. That is when CSI: Miami and CSI: NY fell off the board in 2012 and 2013, respectively. But there are other, non-scheduling and non-financial factors to consider as well sometimes.

The mothership series is in its final legs and far from its glory days but it has earned a proper good-bye that could potentially bring back original stars William Petersen and Marg Helgenberger — the way Steve Carell recently returned for The Office finale — and other notable alums too, like former leading man Laurence Fishburne.

If not, CSI fans will have to look forward to a potential CSI limited series down the road, an idea NBC has been tossing around for its legacy crime drama whose ending was botched, Law & Order.