Since we're still on the Spilotro subject.
I've commented before that if the outfit had not killed him, there was a strong likelihood that he would have flipped, with disastrous consequences for a bunch of guys. He was facing trial on Federal charges at the time of his murder and if he felt that he was backed into a corner, with the law on one side and the mob on the other... This is exactly the sort of situation where a guy rolls.
On that note, it caught my attention that back in 1970, an FBI informant opined that Spilotro was not the kind of guy who could stand up to a long prison sentence. While we know that Spilotro was an accomplished killer, he was also a guy who never actually did any real time (got off acquitted or with slaps on the wrist for everything that he got pinched for), so he was never really tested when it came to this. The identity of this informant is unknown, and it could just be some hater talking stuff, but it stood out to me as it's not something that I typically see an informant saying about a guy.
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Another interesting point is that in 1978, Jimmy Fratianno had told the FBI that Spilotro had made an attempt to pay him off to keep him from talking to the Feds (unsurprisingly, Fratianno seems to have tried to collect the money via his attorney while still cooperating lol). Consequent to this, the DOJ Strikeforce based in SF that was using Fratianno as a witness for the murder of Frank Bompensiero issued subpoenas to Spilotro and several redacted individuals to appear before a Grand Jury that was probably intending to bring charges against Spilotro for attempting to tamper with a Federal witness. No idea if Chicago ordered Spilotro to buy off Fratianno, or if he was doing this on his own, but one can imagine that if this had been his own plan, it could have been another big issue for him back home.
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Going back to Spilotro's crew assignment prior to c.1975 (when Bompensiero reported that Spilotro reported to Lombardo), there, of course, are no quality sources that can clear that matter up with any certainty.
FBI informants and extensive surveillance of Spilotro in the 1960s and early 1970s put him in very frequent contact with the Buccieri crew -- and, in particular, with Turk Torello, who often visited Spilotro's home in Oak Park, though Spilotro was also frequently seen in public meeting with Buccieri, Torello, and Ferriola, as well as spending a lot of time at the Family Amusement Center in Cicero, a front for one of the Buccieri crew's major loansharking operations). Recall again that Frank Cullotta claimed that after an early stint working as a collector for Sam DeStefano, Spilotro became an associate under Torello, sometime around ~1960.
Spilotro was also frequently in the company of Alderisio, as I'm sure we all know. The FBI referred to Spilotro as the "heir apparent" to Alderisio, but in one memo made a point of clarifying that this was not meant to be a statement relating to Alderisio's "position in organized crime", but rather that informant sources had identified Spilotro (along with Obie Frabotta) as having been designated by Alderisio to assume responsibility over a number of business ventures and investments that he controlled when he went to prison (and it's clear that Spilotro was involved in multiple business ventures with both Alderisio and Irving Weiner during this period). The primary source that the FBI had for this -- and it's pretty clear that this source, as with most of the sources in Spilotro's file, was not an LCN member -- further noted that from the interactions that he witnessed, Spilotro and Alderisio seemed to have been of equal status, as he witnessed heated arguments between the two men (he did not describe Alderisio as having been the boss of or in command of Spilotro or anything like this). Hard to really make any statements given the vague info and poor quality of sources here, but the overall picture is consistent with Spilotro being a partner of Alderisio, who assumed interest over some of their ventures when Alderisio was imprisoned and then died, but this doesn't prove that Spilotro was assigned to report to Alderisio (and, we should also note that we don't even know that Alderisio was even a captain at any point in time, as in 1969 Frank Bompensiero, based on a meeting with Alderisio, reported that he understood Alderisio to have been a solider).
In 1979, Red Wemette reported that Frank Schweihs had told him that Spilotro was in a lot of trouble and that Aiuppa wanted to have him take over for the deceased Torello; not as a reward, but in order to get him away from Vegas and keep a close eye on him. So it's interesting to note that in 1971, an informant reported to the FBI that Spilotro and Torello had become bitter "rivals" at that time, as they were both vying for some position of "leadership" that was opening up. Buccieri died of cancer in 1973 and we know that Torello succeeded him as captain, so if the informant was correct here, Buccieri's health may have already been declining at this point, and he presumably wound up tapping Torello to serve as an acting captain for him before succumbing to his illness. 1971 is also the year, of course, that Spilotro packed up and left for Vegas, after getting acquitted on local gambling charges for running a book in the City of Chicago (and for assaulting a CPD cop who busted his operation lol).
The question as to whether Spilotro was "sent" by Chicago's leadership to look over Vegas, or to assist in protecting or mediating conflicts for Rosenthal, or if he just went out there to escape problems he was having in Chicago, remains. FBI sources differed in the 1970s as to the importance of Spilotro in Vegas and the clout or status that he, in fact, enjoyed. But there's also a lot of real estate between "boss of Vegas" and "knucklehead thug", and I believe that Spilotro's actual situation was somewhere in the middle. I think we can safely presume that Spilotro himself probably thought of himself as the former, however. In the late 1960s, a Chicago informant told the FBI that Spilotro was going around saying that he wanted to be boss of the outfit one day, things like this. We know that Fecarotta was alleged to have gone around shooting his mouth off in a similar fashion before he was killed (along with the charges of sexual impropriety also leveled at both men), so I think that a guy who was prone to doing this was basically on a collision course with the leadership of the Family (the type of guy who's unable to humble himself to the organization, even for the strategic purposes of achieving his own goals).