“Crimes conceived in hell don’t have angels as witnesses” is a saying often used in criminal law. To prosecute criminals, district attorneys often have to use witnesses who are “less than angels” to testify against them.
 
“The government cannot produce angels as witnesses to agreements made with Mr. Chagra in hell” was said by an assistant U.S. attorney in 1979. “For a plot hatched in hell, don’t expect to have angels as witnesses” was said by the assistant district attorney at the trial of John DeLorean in 1984. “When you go to prosecute the devil in hell, you wouldn’t call angels as witnesses” was cited in 1989. “Crimes conceived in hell don’t have angels as their witnesses”—the now familiar form of the saying—was cited in print in 1993.
     
 
16 August 1979, Dallas (TX) Morning News, “Chagra convicted in drug smuggling” (AP), pg. 38A, col. 4:
Pierce (Assistant U.S. Attorney Carl Pierce—ed.) responded that the government had indeed made deals and this is a legitimate law enforcement weapon.
 
“Sometimes we have to let a few small fish go to get the big ones,” Pierce said. “...The government cannot produce angels as witnesses to agreements made with Mr. Chagra in hell.”
     
Google News Archive
7 August 1984, The Post (West Palm Beach, FL), “Lawyers Close Arguments in De Lorean Trial” (AP), pg. A4, col. 4:
Perry (Assistant U.S. Attorney Robert Perry—ed.) defended the used of James Timothy Hoffman, a convicted drug smuggler and perjurer, as star witness against De Lorean. saying: “For a plot hatched in hell, don’t expect to have angels as witnesses.”
 
Google Books
June 1989, ABA Journal, pg. 56, col. 3:
“When you go to prosecute the devil in hell, you wouldn’t call angels as witnesses. They are bad people. But even the worst people tell the truth sometimes and they tell the truth when they’ve become redeemed and this informant has been redeemed.”
 
20 May 1990, Daily News of Los Angeles (Los Angeles, CA), “Murder case eludes solution”:
“When you have a crime that occurs in hell,” Hanson said, “you are not going to have any angels as witnesses.”
 
16 March 1993, Denver (CO) Post, “Defendant ‘wasn’t there’” by Howard Pankratz, pg. 2B:
“Crimes conceived in hell don’t have angels as their witnesses,” said Little.
 
24 August 1994, Marietta (GA) Daily Journal, “Kesserling jury deliberating” by Dennis Smith, pg. 2B, col. 5:
Admitting that some of the witnesses in the retrial were of questionable character, Chief Assistant District Attorney Jack Mallard said: “Crimes conceived in hell don’t have angels as witnesses.”
 
Google News Archive
2 May 1995, Milwaukee (WI) Journal Sentinel, “Riegel jury retires for night” by Lori Skalitzky, ‎pg. 3B, col. 5:
“I (Assistant District Attorney William Roach—ed.) told you from the get-go I don’t like Mr. Zamzow. I don’t know anybody who does. But crimes conceived in hell don’t have angels as witnesses.”
 
Google Books
January 1998, ABA Journal, pg. 67, col. 1:
“Who else do you expect to come in here and testify about these crimes?” Safer asked jurors. “Conspiracies hatched in hell do not have angels as witnesses.”
 
Tampa Bay (FL) Times
Pasco man convicted of murder in 2011 death of Hudson drug dealer
Jon Silman, Times Staff Writer 
Friday, May 17, 2013 7:41pm
(...)
He (Assistant State Attorney Chris Sprowls—ed.) took issue with Grieble’s characterizations of Lewka and the other witnesses as drug addicts and the implication that somehow it muddied their testimony.
 
“There’s an old saying,” he said. “Crimes conceived in hell don’t have angels for witnesses.”