Vincent Mroz

In 1948, Mroz went to work for the United States Secret Service.^[9] He was assigned to the presidential protection detail for Harry S. Truman.^[2]

In the fall of 1950, President Harry Truman's household was moved to Blair House on Lafayette Square while the White House was being renovated. He walked between there and his office in the West Wing. On November 1, 1950, Mroz engaged in a gunfight with two Puerto Rican nationalists who were storming Blair House in an assassination attempt on President Truman, upstairs in his quarters. One of the attackers, Oscar Collazo, shot a White House police officer at the guard house and began walking up the front steps of Blair House. After hearing the gunshots, Mroz ran through a basement corridor and stepped out of a street-level door on the east side of the House, where he opened fire on Collazo, shooting him in the chest and dropping him.^[10][11] Mroz stopped Collazo on the outside steps with a bullet to the chest.^{[12][13][14][15]} The incident has been described as "the biggest gunfight in Secret Service History."^[14] Two other officers took part in the shooting of the attackers.

In 40 seconds, a total of 27 shots were exchanged among officers and attackers.^[14] After the shooting ceased, Mroz discovered the body of the second attacker, Griselio Torresola, in the hedges adjacent to Blair House. He had been shot by officer Leslie Coffelt.^[16] Mroz removed a gun from Torresola's body and found two magazines of ammunition in his pockets.^[2]

In December 1951, President Truman, described as being "deeply moved," decorated Mroz and Floyd Boring with silver lapel buttons for their roles in saving him. He said they were "two straight-shooting secret service agents" and gave them formal recognition. ^[17] Collazo survived and was put on trial in February 1951. At the trial, Mroz identified Collazo, "He's sitting right there with a brown suit and a red tie and glasses on."^[18] Collazo was convicted and imprisoned for decades.

Mroz continued to work in the presidential protection detail during the Truman and later Dwight D. Eisenhower administrations.^[2][19] From 1960 to 1962, Mroz was the chief of the Charleston, West Virginia office of the Secret Service, where he gained note for his investigation of a counterfeiting ring.^{[20][21][22][23]} From 1963 to 1965, he was the head of the Kansas City office of the Secret Service.^[9][24][25] He worked for the Secret Service for 26 years. By 1971, Mroz served as Deputy Assistant Director, Protective Services.^[26]

He retired in 1974 as the Deputy Assistant Director of the Uniformed Division. Mroz moved to Adrian, Michigan after retirement. He lived there for 34 years before his death in July 2008. He was the last survivor of the Truman assassination attempt.^[2][27][28]