There have been suggestions made across the internet that there was more than one shooter, and/or, Crooks received help. For example: https://tass.com/world/1817049, which does not have much by way of documentation. Then from the mainstream in India: https://timesofindia.indiatimes.com/world/us/assassination-attempt-on-trump-was-there-a-second-shooter/articleshow/111789785.cms.Peak prosperity also has an analysis of this idea that there were two hostile shooters:https://www.youtube.com/watch?v=LouUbMYb7Bc
And CNN:
"Forensic analysis suggests that as many as three weapons were fired at the Trump rally in Butler, Pennsylvania on Saturday.
The FBI said Sunday that the shooter acted alone.
The first three shots were consistent with alleged weapon A, the next five were consistent with alleged weapon B, and the final "acoustic impulse" was emitted by a possible weapon C, per audio analysis by Catalin Grigoras, director of the National Center for Media Forensics at the University of Colorado in Denver, and Cole Whitecotton, Senior Professional Research Associate at the same institution.
Audio analysis has also confirmed that the gunman was about 360 to 393 feet from the podium, according to forensics expert Robert Maher."
The firing of three weapons, which were not police or Secret Service clearly does show that the gunman Crooks, was not alone.
As Michael Snyder has noted, https://michaeltsnyder.substack.com/p/did-trumps-shooter-have-help:
"One of the best snipers in the entire world, Dallas Alexander, is entirely convinced "that the shooter had help"…
"I'm very familiar with the layout of these types of things and what the jobs should be. And yesterday, what happened, I have no doubt in my mind that the shooter had help from somewhere within an agency, an organization, or the government," said Alexander.
"The second I saw that aerial photo of what they were saying happened, it immediately made no sense to me. You cannot, in broad daylight, get onto a rooftop within what looked like maybe a couple of hundred yards. You can't get into that position with a gun when there's a president speaking. It cannot be done. You don't even need to be a sniper to know that it's the most f—king obvious thing, the most obvious place in the whole world."
"So something happened, and I'm not pointing fingers at anyone. It's too obvious that this guy had help getting there. So whether someone turned a blind eye or it was strategically planned, I mean, it had to be planned to a certain level because events like that and security like that, it's not a small thing. And that is the most obvious place to be."
U.S. Representative Cory Mills also served as a sniper, and during a recent interview he shocked a CNN host by also suggesting that Crooks probably had help…
Former sniper and defense contractor Rep. Cory Mills (R-FL) triggered a CNN host on Tuesday after suggesting that "intentional" failures may have resulted in the assassination attempt on Donald Trump on Saturday.
"The amount of negligence, the amount of mistakes that was made here, I have a very difficult time not leaning myself towards this was intentional, as opposed to fecklessness," Mills told anchor Kate Bolduan.
"If I have a building 160 yards perfectly adjacent to the stage, that's an obvious threat," he continued. "Especially with an elevated position that has overwatch? That's a sniper's paradise."
https://www.youtube.com/watch?v=dwv-7_61qIE
There is photographic analysis at Peak Prosperity https://www.youtube.com/watch?v=LouUbMYb7Bc, which examines another man who was hit, where the bullet passes through the man, then hits the steel rails and disintegrates part of them. It is hypothesised that this was the bullet which grazed Trump's ear and is likely to be a larger calibre than 5.56 mm, maybe .308. That indicates that two shooters were there as Crooks only had an AR 15 in 5.56 mm.
There is also new footage of someone on a water tower, possibly a shooter: https://www.youtube.com/watch?v=ZlNW-U4hH70 with eyewitnesses.