A former high-ranking official of U.S. Immigration and Customs Enforcement provided insight on what's next for the illegal immigrants from the truck smuggling operation.

In 2009, Alonzo Peña became the second-in-command of ICE as deputy director. According to the ICE Foundation website, he managed 20,000 employees, operated a budget of more than $5.7 billion and played a key role in agency's operation.

On Monday, Eyewitness News talked to Peña about the next steps federal agents will make in the investigation. He said once the surviving victims are treated, all of them will be thoroughly vetted. Some of them may end up serving as witnesses for the prosecution.

He said federal agents are interested in individuals who can help forward the investigation.

"Investigation as far as who was involved in this operation, how they were brought into this country, where they were brought into the country, how they were put into the trailer, what other groups were involved in the smuggling," Peña said. "You're looking for people with knowledge who can articulate, that have a good memory, have good facts that will make good witnesses."

Peña said once witnesses are narrowed down, they'll be released on bond. However, if there's a likelihood the person may take off after being released, they'll remain in detention.

ICE will assist them with medical care, counseling and legal resources, which includes access to an immigration attorney. Peña said a third option is for ICE to keep track of the person with a tracking system like an ankle monitor.

Peña said the witnesses will be eligible to apply for an S-Visa, where they may be granted permanent residence for assisting the government.

"A case like this involving 10 fatalities, to prepare a prosecution and to just prepare to conduct this investigation is going to be a lengthy process as well. Because you may have to go back to the home country where these people are from and interview especially, some of the ones that are deceased, go back and find their families, make sure we have the correct identity to who these people are," Peña said.

He said ICE will need continued support from local law enforcement and other agencies.

"In this particular case, ICE is the authority that will investigate a crime that involves the death of at least 10 individuals. I don't think there is any question that SAPD should be taking any heat or criticism for doing the appropriate thing," Peña said.

Eyewitness News reached out to the San Antonio spokeswoman for ICE but did not get a response returned.