CHICAGO (AP) — Snapchat messages to an informant took center stage Wednesday at the opening of the federal trial of a Chicago man accused of soliciting the murder of a senior Border Patrol commander.

Prosecutors say Juan Espinoza Martinez, 37, used Snapchat in a plot that centered on a $10,000 bounty offered for the death of Gregory Bovino, a Border Patrol official. The government also alleged that Espinoza Martinez was a gang member who used the messaging app to put the bounty on Bovino’s life. Espinoza Martinez faces one count of murder-for-hire in the first criminal trial tied to an immigration crackdown that began last year in and around the nation’s third-largest city.

Assistant U.S. Attorney Minje Shin told jurors during opening statements that the case was not about a person “being on trial for expressing strong, even angry views about immigration enforcement policy.” Shin said, “Make no mistake, the evidence in this case will show that what the defendant did was not a joke, was not just him mouthing off, was not him blowing off steam behind a keyboard.”

Defense attorneys argued that the Snapchat messages did not amount to a solicitation to kill, but instead reflected casual talk. Jonathan Bedi, a defense attorney, said Espinoza Martinez’s messages amounted to “neighborhood gossip,” adding: “He’s not guilty because repeating neighborhood gossip is not a crime. Repeating neighborhood gossip is not intending to go commit a murder.”

The dispute turned on how the messages were interpreted by recipients. Prosecutors said the messages in question were sent in October as federal immigration enforcement intensified in the Chicago area, where arrests, protests and standoffs with agents were reported. The defense said Espinoza Martinez sent the messages to his brother and a friend who turned out to be a government informant. At trial, pictures of the messages were shown on screens for the jury.

One recipient called by the government was Adrian Jimenez, 44, who owns a construction company. Jimenez testified that he took the text messages seriously and shared them with a Homeland Security investigator he knew. Jimenez also told the court that he has back pain and walked with a limp to the witness stand. Defense attorneys highlighted his medical issues and asked questions about whether he interpreted the messages as a solicitation.

During cross-examination, defense attorney Dena Singer asked Jimenez whether he was someone who “commits murder for hire.” Jimenez answered, “Nope.” The defense also questioned credibility based on Jimenez’s background, including that Jimenez disclosed he had been convicted of a felony, served prison time, and had previously been paid as a government informant, though he did not offer details about either topic.

The court displayed messages that included, in part, “10k if u take him down,” along with a picture of Bovino. Some messages were sent in Spanish and translated into English for court. Prosecutors previously referred to Espinoza Martinez as a “ranking member” of the Latin Kings, but a lack of evidence led U.S. District Judge Joan Lefkow to bar testimony about the street gang at trial.

Another key witness for the defense was Oscar Espinoza Martinez, the defendant’s younger brother. Oscar Espinoza Martinez testified that he saw a Facebook post about an alleged $10,000 bounty an hour before his brother sent the Snapchats, and that he took the messages as a joke. He testified, “Nobody’s going to do that for $10K.”

The prosecution’s case has drawn attention beyond the courtroom. Bovino and the Trump administration have described the matter as an example of dangers faced by federal immigration agents, particularly from gangs. But lawsuits filed in Chicago have raised doubts about the Department of Homeland Security’s account of the operation. The report said that of roughly 30 criminal cases stemming from Operation Midway Blitz in the Chicago area, charges have been dropped or dismissed in approximately half. It also said that in another high-profile lawsuit that forced Bovino to be deposed, a federal judge found Bovino lied under oath, including about alleged gang threats.

Bovino did not testify. Closing arguments were scheduled for Thursday. If convicted, Espinoza Martinez faces up to 10 years in prison.

Born in Mexico, Espinoza Martinez has lived in the United States for decades, and the federal government said he does not have legal permission to stay in the country. Prosecutors played short clips of his interview with law enforcement after his arrest in which he said he was confused about what prompted the interrogation and that he did not threaten anyone and was not a gang member. In the clips played in court, he said, “I work every day for a living. I’m a union worker.”