The Stig Engström thing is so totally ridiculous like their claim of how he obtained a 357 magnum is that he "borrowed" it from a gun collector friend, then kept it in his advertising firm office, without the collector friend asking for it back or wondering what he was doing with it, then on the night of the murder he leaves the office, first without the gun, spots Palme, returns to the office to grab it, then goes back to shoot him.

Just complete detective fiction brain type shit, personally I think the fascist internal police conspiracy sounds the most plausible, at least compared to "Palme once did a thing that these foreign fascists objected to, this proves the motive!" You had a police scandal at the time of cops going around in plainclothes and baseball caps(hence the nickname of "Baseballigan") and using extreme violence against homeless people and drug addicts.

The same police chief that created the formal groups that these cop gangs were part of, also presided over the Palme investigation, and though the groups had formally been disbanded about 3 years before the murder, the cops basically kept on doing the exact same actions but as regular officers rather than as part of the "Street Violence Groups"(actual name, Gatuvåldsgrupper). These groups were connected to at least two immediate murders but no cop ever faced consequences beyond fines. Palme had reportedly also been personally briefed about Nazism proliferating in the ranks of these cops.

Apparently back in 2010 some papers were declassified which revealed that fellow cops had left internal tips that the baseball gang cops were involved with the murder or the actual gunman themselves, and that a taxi driver had identified one of the cops as hailing his cab 5 minutes after the murder.