If Lee Oswald was a lone nut, who was up to all this shit ?

http://22november1963.org.uk/a-little-incident-in-mexico-city

Oswald in Mexico City: the FBI’s Discovery
The FBI learned on the afternoon of the assassination that it had not been kept fully informed by the CIA of Oswald’s activities in Mexico City. To remedy this, two sets of evidence were sent by the CIA station in Mexico City to the FBI in Dallas, arriving early on the morning of 23 November:
At least one tape recording of a phone call by a man claiming to be Oswald.
Several photographs of the only non–Hispanic man to enter the Soviet compound on the date of Oswald’s meeting there with Kostikov.6
FBI agents in Dallas made an unexpected and ominous discovery: neither the voice on the recording nor the man in the photographs matched the man who was in custody. Someone had impersonated Oswald in Mexico City.7
Oswald’s Assistant or Impostor
Although there was good evidence that Oswald had in fact made at least one visit to the Cuban Consulate and one to the Soviet Embassy,8 several other encounters provided strong evidence that he had also been impersonated:
In two telephone calls to the Soviet Embassy, a man claiming to be Lee Harvey Oswald spoke “terrible, hardly recognizable Russian”, according to the CIA’s translator. Oswald himself spoke Russian very well.9
The man who made the incriminating phone call to Kostikov had also phoned from the Cuban Consulate three days earlier, on Saturday 28 September. In this instance, not only was Oswald impersonated but the phone call or the transcript appear to have been fabricated. The Cuban Consulate and the switchboard at the Soviet Embassy were closed on Saturdays. Silvia Durán, an employee at the Cuban Consulate, who was mentioned by name on the transcript, denied that she had taken part in the call on the 28th.10
Silvia Durán and the Cuban Consul General, who had had three encounters with a man who claimed to be Oswald, both recalled that the man they met looked nothing like either the real Oswald or the man in the photographs.