World War II Radio Heroes: Letters of Compassion, published in 2007 by psychologist Lisa Spahr and Austin Camacho, tells the story of shortwave radio listeners who collected and relayed information broadcast from enemy territory about newly-captured POWs to their families in the U.S.

An entry about Letters of Compassion on Wikipedia has this to say about the effort:

“During World War II, short messages from prisoners of war were often read by studio announcers at stations in Germany, Japan, and other Axis powers countries. A number of shortwave listeners copied the prisoner names and addresses and notified families by mail or telephone, and the practice became known as ‘Prisoner of War relay’ or ‘POW monitoring’. Although the Allied government provided similar services, the families usually heard from shortwave listeners first, sometimes as many as 100 at a time.

“Many wartime listeners were ordinary citizens who discovered they were able access the shortwave bands; a feature included on many premium consumer radios of the era. Times and radio frequencies of the news from Rome, Berlin and Tokyo were published daily on the radio page of The New York Times. Others were dedicated shortwave listeners or DXers who maintained an ongoing interest in long-distance radio listening as a hobby. Still others were licensed amateur radio operators who were, as a group, banned from transmitting due to wartime restrictions, but often kept their listening gear in operation.”

In May 1943, Sergeant Albert Rosenblum’s family received a host of these cards from shortwave listeners around the U.S. The writers reported they had heard Albert’s name and his home address broadcast from Rome.

In addition to the news conveyed, concern and encouragement these strangers expressed must have been a great comfort to the Rosenblums.

For Albert Rosenblum’s full story, read the following post:
A Family in Service.

Helen Barrett
317 Burnet Park Dr.
Syracuse, N.Y. [New York]

Mr. Horace Rosenblum
Route 1
Box 48
Swan Lake, N.Y.

May 8, 1943

Dear Mr. Rosenblum,

Last evening I was listening to my short-wave radio and tuned in on a news broadcast from a station in Italy. The news was in English, and among other information, were the names, addresses, etc. of American soldiers who are “Italian prisoners”. Your son’s name was among those given:

Albert Rosenblum
#6701591

Perhaps you already have this information, but as a fellow American with a young brother in the war I feel it is my duty, really, to send this news on to you.

Hoping you will be hearing good news of your son very soon, I remain—

Sincerely yours,
(Miss) Helen Barrett

Box Holder
R. 1, Box 48
Swan Lake, N. York

May 6, 1943
10:45 p.m.

Dear Folks:

Tonight at 10:45 the Italian Radio listed as a prisoner somebody from your box number. I found it impossible to understand the name, but I trust my card will relieve your worries if one of your loved ones has been reported missing.

Please let me know if you hear from others and when you first heard of the broadcast.

With best wishes for his safe return, I remain,
Sincerely yours

Curtis Taylor
102 Grove Place, N. York

5115 Izard Street
Omaha, Nebr. [Nebraska]

Mr. Harry Rosenblum
Route 1 Box 48
Schroon Lake
New York

(The name Shroon Lake is crossed out and above the address is written “Try Swan Lake N.Y.” In fact a town called Shroon Lake does exist, for the front of the card bears its postmark.)

Dear Sir—

Thursday May 6th at 7:45 P.M. central war time, the Italian short wave radio, read the name of Albert Rosenblum service #6701591 as a prisoner of war in Italian hands. I am not sure I caught the first name correctly. Your name, the route number, the box number, and the service number came through clearly. The name of the town was not clear, it sounded more like Swan Lake but I find no such town listed in N.Y.

I hope this card reaches you as my experience had been that these announcements are authentic. If you receive this I would be interested in knowing whether you get any other reports and particularly whether you receive verification from the War Department.

John F. Fike

From I. S. B.
Franconia
N. H. [New Hampshire]
Box 12

From Robert Rosenblum
Father Harry Rosenblum
Route 1 Box 48
Shrone Lake
New York
Swan Lake, N. Y.

(A note on the address side of the postcard reads: “Evidently from broadcasts + reply letters to similar cards men are not hearing from home and are getting anxious”)

May 6—7.45 P.M EST. [Eastern Standard Time]

Rome Italy has just broadcast name + address on this card (near as writer could hear it) requesting listeners in U.S.A. to relay by mail the information to you that your son is now. As now a “Prisoner of War in Italian hands, Italy” This that u may know where he is and where to address his mail

Writer would like to know if u receive this letter O.K, and if the Red Cross refuses to take mail to him unless + until sender has been officially notified by war department.

S. Edison
14 W. 10 St.
N.Y.C. [New York City]

May 6, 1943
14 West 10th St.
N.Y.C.

To whom it may concern,

You have, no doubt, been informed of the fact that Albert Rosenblum is interned in Italy. This evening his name was announced by Rome radio as one of the American prisoner, and your address was given; so just on the chance that you hadn’t yet heard, I decided to write this note.

Sincerely,
Sidney Edison

F. Memory
509 S. Front St
Wilmington, N.C. [North Carolina]

Mr. Harry Rosenbloom
Rte 1 Box 48
Swan Lake, N.Y

Wilmington, N.C.
May 6, 1943

Dear Sir—

In listen to Short Wave Italian Radio Station I heard your Sons name called—Albert Rosenbloom along with your address—They announced your Son as prisoner of war in Italy.

I thought I should write you the above Information though you probably have been notified. My regrets.

Sincerely
FRANK MEMORY

153 Suppes Ave.
Johnstown, Pa. [Pennsylvania]

Mr. Harris Rosenbloom
Route 1, Box 1
Swanlake, N.Y.

May 6, 1943

Dear Sir,

Tonight over the enemy radio, I picked up a broadcast informing any American listeners of Americans who are prisoners of war in Italy. Your son, Sergeant Alfred Rosenbloom, was one. Since the announcer talked extremely fast, I was unable to get the serial number. If I can be of any further service to you, just drop me a line. Until then, I remain your faithful servant,

Paul Kay

Newark, N.J. [New Jersey]
May 6, 1943

Dear Mr. Rosenblum:

I heard over a shortwave broadcast that your son Sgt. Rosenblum is a war prisoner in Italian hands.

Respectfully
Mrs. J. Alvarez