By 1945, the Mattson Kidnapping remains active and during the depression era years before, kidnapping was "big business."
Here's part of a paragraph shown in a 1939 letter to the Attorney General from J. Edgar Hoover covering a seven year period:
"Since the passage of the Federal Kidnapping Statute on June 22, 1932, the Bureau has performed investigative work in 144 actual kidnappings. All but two have been solved. The two unsolved cases are those involving the abduction and murder of Charles Fletcher Mattson, Jr. at Tacoma, Washington, [Dec. 1936] and Peter Levine at New Rochelle, NY [Feb. 1938]. "
"In the kidnapping cases handled by the Bureau, there have been 290 convictions, sentences imposed have totaled 11 deaths, 42 life, 3,493 years, 2 kidnappers have been lynched, 8 committed suicide, 8 were killed by law enforcement officers, and 7 were murdered by their own gang members."
"At the present time, 93 special agents and 10 Technical Experts of the Bureau are exclusively assigned to the Mattson and Levine cases...."
Another part of the letter reveals agents on the average were assigned an average of 18 cases each (many of them major investigations) and that the Federal laws passed of 1934 had placed undue strain on the Bureau due to lack of agent personnel. It was generally agreed at FBIHQ that an assignment of 10 cases per agent was "manageable." At the time of this 1939 memo, there were 647 special agents.
Kidnapping cases during the early days, as is still the policy today, require the responding field office to drop all other investigative matters, and reassign manpower as needed. Quite a few of these kidnappings involved children and more than most are aware of; some have been long forgotten. Many, as in any major crime, contained long lists of those who confessed; had nothing to do with the kidnapping, and sent agents and police on fruitless pursuits of leads which ate up time and money.
To my knowledge, as of today, the Mattson and Levine kidnappings remain unsolved.