In United States. v. Alvarez-Sanchez (1994) 511 U.S. 350, the high court adverted to a hypothetical violation of title 18, section 3501 of the United States Code--"if state or local authorities, acting in collusion with federal officers, were to arrest and detain someone in order to allow the federal agents to interrogate him in violation of his right to a prompt federal presentment." (Alvarez-Sanchez, supra, 511 U.S. at p. 359.) Pursuant to Anderson v. United States (1943), "a confession obtained during such a period of detention must be suppressed if the defendant could demonstrate the existence of improper collaboration between federal and state or local officers." (Alvarez-Sanchez, supra, at p. 359.) In Anderson, "a local sheriff, acting without authority under state law, arrested several men suspected of dynamiting federally owned power lines during the course of a labor dispute and allowed them to be interrogated for several days by agents of the FBI. Only after the suspects made confessions were they arrested by the federal agents and arraigned before a United States Commissioner. The Court held the confessions to be inadmissible as the 'improperly' secured product of an impermissible 'working arrangement' between state and federal officers." (Alvarez-Sanchez, supra, 511 U.S. at p. 359, fn. 4, quoting Anderson, 318 U.S. at p. 356.)