The Truman assasignation attempt was...
1949/1950, during the renovation of the White House and the Trumans, were occupying the Blair house across the street.
The attackers were on a Puerto Rican terrorists that did a frontal attack and killed three Secret Service agents and wounded five(?) others.
The Trumans were not in residence at that time.
WJC pardoned the last remaining terrorists (2) before leaving the White House, not informing the S.S. until the last minute and over their objections.
A year later, the same group attacked the House of Representative during session from the Gallery, and wounded several Representatives and killed(?) some Capitol Police.
There are in the ceiling the bullet holes from that attack.