One of the cornerstones of President-elect Donald Trumps campaign was a mass deportation plan that Trump promised would be the biggest in American history. Now that the election is over, many are asking what that plan would look like.Theres an extremely high level of concern, said Denver City Councilwoman Flor Alvidrez. I would say people are on edge. A vast majority of my constituents are on edge.Denver7 Investigates took the concerns of the councilwoman and many other Coloradans to John Fabbricatore, the former field director for Immigration and Customs Enforcement (ICE) for Colorado and Wyoming.Since his retirement two years ago, Fabbricatore has stayed connected to the developments at the U.S. border and has closely monitored the proposals from the Trump campaign. He regularly visits the border, having been there nine times since he retired. He also recently wrapped up a bid for Congress in Colorado's 6th Congressional District as the Republican nominee, finishing behind incumbent Jason Crow.Fabbricatore acknowledged the concerns and hoped to ease them, saying the first step would be to go after criminal noncitizens and national security cases.My goal is to really bring the temperature down about what's going on, he said. I really do believe a lot of people are looking at this and they have the idea that there's going to be these checkpoints and there's going to be immigration officers pulling people out of cars because they are a different ethnicity... This is not what immigration officers are going to be doing.But Fabbricatore recognizes that the concerns will still linger. Alvidrez, who has been hearing those concerns from constituents, also said shes hearing them at home from her own son.The first thing he asked me was, 'Is Trump coming to Denver to take away all my new classmates? she said.Fabbricatore, however, said the effort is going to be legal, lawful and humanitarian, with the focus being on criminals.We will go after criminals and national security threats first, and we already know who many of these already are, he said. We know who they are. We know that they're criminally involved in crimes in the United States and they are deportable.Fabbricatore said the federal government is aware of more than 600,000 convicted and accused criminals living in the U.S. as noncitizens.We know that there are 13,000 people who have been convicted of homicide in that group of 600,000. There's over 18,000 convicted of sex offenses, he said.Alvidrez said she felt Fabbricatores comments calmed the waters and provided clarification. Let's make sure we build a coalition, she said. This isn't time for hate, this isn't time for divisiveness. This is a time to be neighborly and come together as a community to make sure everyone feels welcome and safe.Fabbricatore stressed that he is not opposed to immigration, but it needs to be done through legal means. He also said because of the magnitude of the number of convicted noncitizens, the process will take years and require a significant commitment to staff hours and dollars.Im all for legal immigration. The United States is a melting pot, and we should have a good process for people coming into this country, he said. But they need to be vetted, and it needs to be legal.