I wasn't aware that Oswald stopped off for 5 days in Helsinki on his way to the Soviet Union.
Oswald sailed from New Orleans to Le Havre in France. He then made his way across the English Channel to arrive in Southampton.
From Southampton he made his way to London where he flew from London to Helsinki in Finland.
He stayed for 5 days in Helsinki while he waited for a tourist visa into the Soviet Union.
He then traveled from Helsinki to Moscow.
On 25th May '64, J. Lee Rankin wrote to Richard Helms (CIA) for information about the speed with which Oswald got his visa to enter the Soviet Union.
Rankin had heard that it would usually take at least week for a visa to be granted.
Oswald arrived in Helsinki on the 10th October '59 and was granted a visa by the 14th.
This might not seem too unusual but there was another, slightly more concerning possibility.
The 10th was a Sat.urday and the Soviet Consulate closed early and was closed all day Sunday.
If Oswald arrived late on Sat.urday it would mean he would have to wait until Monday morning, the 12th, to apply for his visa, meaning it only took two days to get his visa. This would be considered highly unusual:


There is a follow up to this request on June 1st but without much extra information other than the CIA having a presence in Helsinki.

Then I came across this article about the Finnish Security Intelligence Service (SUPO) declassifying documents pertaining to Oswald's stay in Helsinki.
It turns out Oswald arrived late on Sat.urday and had to wait until Monday (the 12th) to apply for his visa and received it within two days (Wednesday the 14th).
He then traveled to Moscow on the 15th.
https://yle.fi/a/74-20064205The article reveals something quite strange - when Oswald initially arrived in Helsinki he seemed to know he would only be staying 5 nights.
How could he know that?
How could he have his visa application expedited?
Who did he know in Helsinki?