"One of you in your testimonies called these laws to prosecute 'toothless.' Could explain to me -- why are existing straw purchase laws 'toothless'?" Maloney asked.
Issa butted in to say that their ATF agent's opinions on U.S. gun laws would not be "considered valid testimony."
"I want to caution the witnesses that the scope of this, your testimony here is limited, and that it's not about proposed legislation and the like and under House rules would not fall within the scope of this," Issa said. "So, anecdotally you can have opinions but ultimately it would not be considered valid testimony.
Eventually, ATF Special Agent Peter Forcelli gave an answer.
"My opinion, ma'am, is that with these types of cases, for somebody to testify against members of a cartel where the alternative is seeing a probation officer once a month, they will opt towards not cooperating with the law enforcement authorities," Forcelli said.
Rep. Gerald Connolly (D-VA) also chimed in to encourage witnesses to speak freely.
"I want to respectfully suggest, however, that I think we urged you to speak freely at some risk, and that means answering questions freely, without interference from any other member of this committee," Connolly said.
"We don't censor content here. The hearing has a scope, but if you feel an answer to a question requires amplification, you don't need to be mindful of the scope and and an individual member of this committee has a individual right to ask questions, solicit answers without censorship," Connolly said. "I want you to have that confidence just as we begin this hearing, urging you to speak freely, so you can speak freely and answer questions, including questions by this member."