Representative Tom Kean Jr. of New Jersey has remained out of the public eye for nearly three months. This unusual absence has drawn increasing attention, especially with the upcoming New Jersey primary on Tuesday, where his name appears on the ballot.

The situation began to unfold in March when a political website reported that Mr. Kean missed a week of votes in Washington. His last recorded vote in Congress was on March 5.

Initially, missing a few votes might not have been a major concern. However, after the Easter recess, other members of Congress, including two of Mr. Kean’s Republican colleagues from New Jersey, expressed surprise at his unexplained absence. They reported having no information about his whereabouts. Further frustration grew when Republican leaders revealed that their attempts to contact Mr. Kean via text had gone unanswered.

The intrigue surrounding Kean’s absence gained momentum when Dan Scharfenberger, his chief of staff, commented to The New York Times in May, “There’s no cameras where Tom is.”

With the primary approaching and Mr. Kean unchallenged by Republican opposition, his only known campaign activities involved phone conversations with a New Jersey political journalist and Republican leaders in his district. During one call, Joe LaBarbera, chairman of the Republican Party in Sussex County, inquired if Mr. Kean needed anything. Kean’s response was, “Just your prayers,” according to LaBarbera.

Mr. Kean’s absence has been attributed to a “personal medical issue,” though his aides have not provided specific details. They have reassured since April that he is expected to recover fully and return to work soon.

As the day of the congressional primary arrives, the mystery of Mr. Kean’s absence persists, leaving many unanswered questions despite efforts to resolve the situation.