Dear Mr. Jansen,
Thank you for posting your request on History Hub!
Official Military Personnel Files (OMPFs) and individual medical reports for enlisted men of the U.S. Army who were separated from the service after October 1912 and prior to 1955 are in the custody of NARA's National Personnel Records Center in St. Louis. In many cases where personnel records were destroyed in the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Please complete a GSA Standard Form 180 and mail it to NARA's National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. Please fill out the form to the best of your knowledge. If there are things the form asks for which you do not know, you can leave those spaces blank, however the more information you provide, the easier it will be to locate the correct records. When you mail the form, you can also include an attachment providing additional information. For records affected by the fire, information such as date of death; last assigned unit (see below); and place of entry into service may be useful. For more information, see Official Military Personnel Files (OMPF), Archival Records Requests.
Individual Deceased Personnel Files (IDPFs) from 1940- 1976 for personnel with surnames that begin with A-L are in the custody of the National Archives at St. Louis (RL-SL), P.O. Box 38757, St. Louis, MO 63138-1002. For access to these records, please contact RL-SL via email at firstname.lastname@example.org.
In regard to unit information, the 4th Cavalry Reconnaissance Squadron was a component of the 4th Cavalry Group, and the Group was originally designated the 4th Cavalry Regiment. We searched the World War II Operations Reports, 1940-1948 in the Records of the Adjutant General's Office, 1905-1981 (Record Group 407) and located records for the 4th Cavalry Reconnaissance Squadron, the 4th Cavalry Group, and the 4th Cavalry Regiment. We checked the October 1944 after action reports for the 4th Cavalry Reconnaissance Squadron for October 5, 1944 (file CAVS-4.0.3 7784) and found Staff Sergeant Jansen listed as missing. Presumably his body was located and identified after the report was made. The report states that he was in Troop B at that time. The histories in the for the 4th Cavalry Group also include him in a list of soldiers that won the Bronze Star. We also located a general order in the files of the 4th Cavalry Group (file CAVG-4-1.13) awarding him and others the Bronze Arrowhead Device for participation in the D-Day Normandy landings on June 6, 1944. There may be additional references to him in the unit records, and even if there are not, the unit records as a whole provide insight into activities of his unit. To order copies of these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at email@example.com.
We also located two records in the custody of the National Archives at College Park - Motion Pictures (RDSM) relating to the 4th Cavalry during World War II which have been digitized and may be viewed online through the Catalog. There may be additional motion pictures relating to the unit. To request a search for motion pictures, contact RDSM via email at firstname.lastname@example.org.
Photographs of various U.S. Army activities and subjects during WWII are in the custody of the National Archives at College Park - Still Picture (RDSS). Please contact RDSS via email at email@example.com for more information.
For general information about the unit, we also suggest searching online and through libraries and retailers for histories of the unit. The following is a sample of the sources we located.
- https://history.army.mil/documents/ETO-OB/82ABD-ETO.htm (see Cavalry units listed as Attachments)
- https://history.army.mil/documents/ETO-OB/4ID-eto.htm (see Cavalry units listed as Attachments)
- https://history.army.mil/documents/ETO-OB/1ID-eto-ob.htm (see Cavalry units listed as Attachments)
In regards to your request for information about his relatives, there may be next of kin information listed in his OMPF and IDPF. There also may be listings for him and his family in the 1920, 1930, and 1940 census. For information about accessing these records, please see or page here: https://www.archives.gov/research/genealogy/census
Many genealogical sites also offer access to other records such as the Minnesota Death Index, the Social Security Death Index that might allow you to identify the time and place of death. We see from your Facebook page that you already have a family tree identifying his siblings with their dates of death. If you can locate obituaries for them, the obituary may include information about surviving relatives as well as information about funeral homes and religious institutions which you could contact.
Other institutions which may be able to assist you in researching Staff Sergeant Jensen include All Veterans Memorial in Hubbard County, the Park Rapids Area Library, the Hubbard County Historical Society, and the Minnesota Historical Society.
We hope this information is helpful. Best of luck with your research!