"What a surprise to find it," Kapitein told ABC News. "The tone of the text -- so sad, so hopeless. [It] made a great impression on us."
Kapitein of Urk, the Netherlands, said he and the other worker were updating an old bathroom door during a routine job in a home located in the village of Bilthoven.
The message, written in Dutch, read:
The message bore the date, April 23, 1942.
Sajet and Zilberstein also apparently included their original home address in Amsterdam, different from the house in Bilthoven, where Kapitein said he assumes the couple was hiding.
"It's sad that we found this story after 73 years," he said. "It's difficult to find the answer."
Kapitein said he is trying to locate relatives of the couple by searching "archives all over the world," and investigating what could have become of them after the war.
He still has the door in his possession, but said the Yad Vashem Museum in the Netherlands, has contacted him in hopes of trying to authenticate and take ownership of it.
"Yad Vashem is currently researching its archives for more information regarding the couple who wrote their names and personal details on the door. However, we have yet to confirm their identity," the museum said in a statement. "Yad Vashem would be pleased to receive the door if Mr. Kapitein wishes to donate it to our collection, as it bears witness to the fate of the Dutch Jews during the Holocaust."
ABC News' Jessica Velmans contributed to this report.