Rarely do drug traffickers pick up their phones and openly conduct their business, plainly stating the quantities of drugs they would like to buy and prices they would like to pay.
Instead, they generally use coded language in an attempt to obscure their activities. And even when investigators think they know the meaning of the conversations they catch on wiretaps, they still have to convince a jury that they've interpreted the interactions correctly.
The difficulty of that job was on display this month in the case of Danilo Garcia, who was accused of trafficking heroin from New York to Baltimore after a long surveillance operation. A federal appeals court threw out his conviction this week, citing problems with an FBI agent's testimony about Garcia's recorded conversations.
Authorities said members of Garcia's crew would drop zeros from numbers to make them seem smaller and alleged they could tell somebody had heroin through use of the phrase "showtime."
Garcia was convicted with the help of wiretap evidence, but the appeals court said investigators did not clearly explain the basis for their interpretations. FBI agents can share their opinions based on their law enforcement expertise, but are not allowed to use information from witnesses in a specific case, which the court considers hearsay, the judges said.
The trouble arose because FBI Special Agent Carrie Dayton was called to testify both about the meaning of the calls and to the facts of the extensive investigation.
In one example singled out by the appeals judges, Dayton testified that "a 145 point" meant 145 grams of heroin — a view seemingly confirmed when agents seized that amount of heroin from one of the people on the call.
But Judge Andre M. Davis wrote in an opinion that the basis for Dayton's testimony was unclear.
"This exemplifies occasions, and we discern many of them, in which Agent Dayton simply substituted information gleaned from her participation in the investigation … for ostensible expertise," he wrote.
Dayton's testimony, played out over 18 separate visits to the witness stand, was so important to the government's case that the judges ruled that Garcia is entitled to a new trial.
The U.S. attorney's office said it intends to prosecute him again and have also left open the possibility that they could challenge the appeals court ruling.