PGP key 0xD0220E4B is not listed on the Tor website.

The signature found at https://www.torproject.org/dist/torbrowser/3.5.4/sha256sums.txt-boklm.asc was created by a key (0xD0220E4B) that is not listed on https://www.torproject.org/docs/signing-keys.html.en