A sometime USN Captain, who worked with William F Friedman. Between 1948 and 1950 he was Director of Investigations in the "Naval Security Group" .
Made a presentation at the 1972 symposium organised by Mary D'Imperio. In 1976 he gave a paper in which he showed that the Voynich Manuscript must have been written by at least two different people.
His papers, on a Voynich Manuscript can be found here 
The Spanish Wikipedia biographical page is . Mentions in the UK Wikipedia are here  and here 
In February 1941, Captain Abe Sinkov and Lieutenant Leo Rosen of the US Army, and US naval Lieutenants Robert Weeks and Prescott Currier, arrived at Bletchley Park bringing, amongst other things, a replica of the 'Purple' cipher machine for the Bletchley Park's Japanese section in Hut 7.