International drug lords sometimes kill people who plan to take the witness stand against them. It has happened so often in Mexico, for example, that some have described the country’s witness protection program as a witness detection program, or a hit list.

As the authorities in New York prepare for the trial next month of the world’s most famous drug lord — Joaquín Guzmán Loera, who is best known as El Chapo — they have taken extraordinary steps to keep those who will testify from getting killed. Mr. Guzmán’s lawyers say those strict protective orders have made mounting a strong defense more challenging.

Here are few of the ways the prosecution has kept the witnesses, and issues at the trial that concern them, under a veil of secrecy, and why:

Shielding names on court documents

From the moment Mr. Guzmán was extradited to Brooklyn from Mexico last year, prosecutors have argued that he presents an “extreme danger” to the numerous former allies, rivals and underlings who will ultimately testify against him.

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The government has repeatedly refused to identify the witnesses in any public papers, saying that if it does, the Sinaloa drug cartel, which Mr. Guzmán ran for 20 years, could easily seek revenge.