The memos of Supreme Court clerks evaluating death row petitions usually consist of a brief review of the facts and then a dispassionate legal analysis as to whether the court should hear the case.

Not so for Ted Cruz.

Mr. Cruz, the most ardent death penalty advocate of Chief Justice William H. Rehnquist’s clerks in the 1996 term, became known at the court for his signature writing style. Nearly two decades later, his colleagues recall how Mr. Cruz, who frequently spoke of how his mentor’s father had been killed by a carjacker, often dwelled on the lurid details of murders that other clerks tended to summarize before quickly moving to the legal merits of the case.

“That, I think, was a special interest of his,” said Renée Lerner, then a clerk for Justice Anthony M. Kennedy, who said she was impressed with how deeply Mr. Cruz delved into the facts and history of a murder case. “It was unusual for a Supreme Court clerk to do that.”

Other clerks, however, had a less admiring view. In interviews with nearly two dozen of Mr. Cruz’s former colleagues on the court, many of the clerks working in the chambers of liberal justices, but also several from conservative chambers, depicted Mr. Cruz as “obsessed” with capital punishment. Some thought his recounting of the crimes — “dime store novel” was how one described his style — seemed more appropriate for a prosecutor persuading a jury than for a law clerk addressing the country’s nine foremost judges.