Here is the map of 1968 Primaries, notice 36 of the 50 states (72%) did NOT have a primary in 1968:
http://en.wikipedia.org/wiki/Democratic_Party_ (United_States)_presidential_primaries,_1968
Robert Kennedy had won four traditionally REPUBLICAN states (California, Nebraska, Indiana and South Dakota, Yes, California was a traditional GOP state at that time, just as Texas was a traditional Democratic State. in fact in the fall election Nixon would win California AND Humphrey would win Texas in 1968).
Kennedy was already behind Humphrey in the number of delegates even AFTER California, that is how much support Humphrey had in the Caucus states.
The biggest problem was Robert Kennedy's lack of support in DEMOCRATIC leaning states, of the 14 states having primaries in 1968, California,Oregon, Nebraska, South Dakota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, New Jersey, Massachusetts, New Hampshire and Florida, Nixon in the fall election would win all but Pennsylvania and Massachusetts. Thus the 1968 primaries were a better indicator of how the GOP would do in the fall election then any Democratic candidate.
A similar situation developed in 1972, McGovern won the Nomination via the Primaries, but then lost every state in the Union except Massachusetts to Nixon in 1972, my Father noted that in some voting districts in Pittsburgh Pa, Nixon received almost 1/2 of the votes, something unheard of before or since, that is how much McGovern was opposed among Democrats in the Mid-West. One of the the old joke about Pittsburgh is that it is a Mid-West City located in an Eastern State. The primary reason for this is that do to the Appalachian Mountains, it is easier and often faster to go to Chicago then go to Philadelphia from Pittsburgh, yet Philadelphia and Pittsburgh are in the same state. This division was best seen in the 1980 Pennsylvania Primary, every group that went for Edward Kennedy in 1980 in the Eastern half of Pennsylvania, went for Jimmy Carter in the west. Kennedy had way less support in the Mid-West (Pittsburgh, Cleveland, Chicago, Minneapolis/St Paul) then he had on the Coasts, and that was a problem he could NOT find a way around.
My favorite observation was the report of Robert Kennedy's campaign manager, Larry O'Brien, who thought even after the win in California Robert Kennedy's chance of winning the nomination was slim. (His observation is reported in the Wikipedia report reference above).
Sorry, Robert Kennedy was BEHIND in the delegate count even with his win in California, and Humphrey was winning because the key to the Nomination in 1968 was still the Caucuses, and Kennedy was losing the fights in the Caucuses.
2. I use the term "CONCLUSIVE" deliberately for a mere opinion, even based on the evidence is NOT enough, you have to SHOW with CLEAR and CONVINCING evidence that anyone but Sirhan did the shooting AND NO SUCH EVIDENCE IS KNOWN. All of the evidence can be explained by Sirhan being the only shooter, this includes dismissing the "14" shots as echos and/or holes in the plaster/Wood do to other causes. You may not LIKE that standard of review, but it is the standard the courts would demand in any trial as the one Sirhan is seeking (Remember Sirhan was CONVICTED and the appeals of that conviction was done decades ago, thus the burden to re-open the trial is on him to show he is innocent NOT on the state to show he is guilty. That is the standard of review as Sirhan's case stands today.)
Given that level of "proof" I have NOT seen any "Conclusive" evidence to show someone else did the shooting. You may NOT like that explanation of the evidence, you may reject that explanation of the evidence, but it is explanation accepted by the Courts and the one that must be disproved.
Side note, while I use the term "Disprove" it is not quite the legal test at this type of trial. Given this is a request for a new trial based on new evidence the Court and the Prosecution can also reject the above explanation. At this type of trial the burden in on Sirhan to show he did NOT commit the crime or could not have committed the crime, i.e. he is innocent, which is a much harder burden of proof then he had when first arrested, when the burden was on the STATE to show Sirhan was guilty of the crime. Given that the evidence can be explained with Sirhan being the sole shooter, it is a tough burden of evidence to show and more likely then not the Court will uphold the Conviction based on the unpleasant fact the evidence CAN be explained by Sirhan being the single Shooter. If the Court finds that the evidence can be explained by whatever theory the court wants to adopt and that theory includes Sirhan being a Shooter, then his conviction must be upheld. This is why he has sat in a California Jail since 1968, hard to prove he is innocent.