1930 U.S. Census, Baltimore City, Maryland
6th Ward, Tract 10, Block 95, Enumeration District 4-70, Supervisor’s District 4, Sheet 1A
133 Bradford Street
Dwelling 3, Household 3
Cohen, Harry, head, owner, $2,000 in real estate, owns radio set, not on farm, male, white, age 27, married, not in school, can read and write, born in Russia, both parents born in Russia, native language Yiddish, immigrated in 1906, not naturalized, speaks English, occupation clerical worker for postal telegraph, wage worker, at work previous day
Cohen, Catherine, wife, female, white, age 24, married, not in school, can read and write, born in Maryland, both parents born in Maryland, no occupation
Cohen, Carroll R., son, male, white, age 3-6/12, single, not in school, born in Maryland, father born in Russia, mother born in Maryland, no occupation
Cohen, Irene M., daughter, female, white, age 6/12, single, not in school, born in Maryland, father born in Russia, mother born in Maryland, no occupation
Household 4
Kopp, Margaret, mother, female, white, age 45, unclear mark as to marital status, not in school, can read and write, born in Maryland, both parents born in Germany, speaks English, no occupation
Kopp, Milton C., brother, male, white, age 15, single, in school, can read and write, born in Maryland, both parents born in Maryland, speaks English, occupation messenger for postal telegraph, wage worker, at work previous day
Kopp, LeRoy E., brother, male, white, age 5, single, not in school, born in Maryland, both parents born in Maryland, no occupation

1940 U.S. Census, Baltimore City, Maryland
6th Ward, Enumeration District 4-100, Sheet 3B
133 Bradford Street, visited number 64, home owned, home value $1,250
Cohen, Katherine E., head, female, white, 36, married, not in school, highest grade attained 8, born in Maryland, living in same place in 1935, at private work, hours worked 40, telephone operator for postal telegraph, private work, weeks worked 52, income 769, has other income
Cohen, Carroll I., son, male, white, 14, single, in school, highest grade attained 5, born in Maryland, living in same place in 1935, not at work, no other income
Cohen, Irene M., daughter, female, white, 10, single, in school, highest grade attained 3, born in Maryland, living in same place in 1935
Kopp, Margaret, mother, female, white, 55, divorced, not in school, highest grade attained 4, born in Maryland, living in same place in 1935, engaged in housework, no other income
Kopp, Leroy, brother, male, white, 15, single, not in school, highest grade attained 4, born in Maryland, living in same place in 1935, not at work, no other income

A death notice in The Baltimore Sun stated:
Kopp.—On May 21, 1959, LeROY E., of 2205 East Jefferson street, beloved brother of Katherine E. Cohen and Milton C. Kopp.
Funeral from the Schimunek Funeral Home, 2061-03-05 East Madison street, on Monday at 8 15 A.M. Requiem High Mass at St. Wenceslaus Church at 9 A.M. Interment in Meadow Ridge Memorial Park Cemetery. Visiting hours, 2 to 10 P.M.
[The Baltimore Sun, 23 May 1959, page 22.]