The president of the Denver Police Protective Association plans to tell members of Congress that the city is less safe because of an immigration ordinance the city adopted late last year.

Detective Nick Rogers will testify in front of the House Border Security and Immigration Subcommittee, under the umbrella of the House Judiciary Committee, on Thursday morning.

According to a statement from DPPA, the union was invited to Washington to speak about the opioid crisis' impact on Denver, as well as Bill 17-0940 - the immigration ordinance the city put into effect in October. Last month, the Department of Justice said Denver was one of 23 local governments that could lose federal funding because of that policy.

TESTIMONY

Rogers has 32 years of experience with Denver Police, and has worked on the narcotics unit for the last two decades. He was elected as the president of the DPPA, which represents more than 1,300 officers, 10 years ago.

An early copy of Rogers' testimony has been posted to the Judiciary Committee's website. In the four-page document, Rogers details his résumé, including his personal experience with drug crimes. He then goes on to tie Denver's opioid epidemic together with immigration.

Rogers says the buyers he dealt with were often young white men who started using opioids at home, who would then go to the streets to buy medication, often from people here illegally.

"Beginning in 2006, I began to see heroin on the streets of Denver. As the arrests grew and I was able to interview both the sellers and buyers, it became apparent the source of the heroin was coming from Mexico and the parties selling it were also from Mexico and Honduras. Early on, I found that almost all the buyers of the heroin were middle class, white, young adults from the 3 suburbs. Each one had a story to tell but the overwhelming consistent part of the story was that they started their own opiate addiction by taking their parents left over pain pills -- slowly becoming addicted to them. Some had been involved in an accident or had surgery, with the common thread of taking oxycodone and becoming addicted to it. Each of the stories wound up on the streets of Denver because buying pills on the street is too expensive and they all turned to the cheaper opiate, heroin.

"The heroin dealers also had a common story. They were mostly young, 18 to 25-year-old, illegal aliens from mostly Mexico, but as the years went by, some started coming from Honduras and Nicaragua. They were all in possession of several ounces of heroin and a fake ID from Mexico (Sinaloa was most common). Some of these arrests led to what was known as “the office:” A location, usually a higher end apartment, which was used only to stash the heroin and money. Many of these “offices” produced tens of thousands, if not hundreds of thousands, of dollars in cash waiting to be sent back to Mexico. Each office also produced an average of one pound of heroin located there.

"I began to see a disturbing trend. I started to arrest the same parties twice. For example, working in an undercover capacity, I bought heroin from an illegal alien, arrested him, charged him with distribution of a controlled substance, and had an immigration detainer placed on him, believing this would end that suspect’s involvement in the narcotics trade. Several months, to a year or so later, I arrested the same suspect who was now wanted for failing to appear on the first case, and now in possession of heroin a second time. The only change was the suspect was now in possession of a fake ID, with a different name. This became common practice in my unit, as well as other narcotics units around the City: Arresting illegal aliens for possession of large amounts of heroin, cocaine, and methamphetamine who were now living under fake names, all the while being wanted on failing to appear on other drug charges.

Rogers writes that he would often contact ICE agents in Denver to assist in investigations, whether it be to conduct interviews, or put a detainer on someone in this country illegally. He says that changed when Denver enacted its new immigration policy, which prohibits any city employee from using Denver resources to help enforce federal immigration law.

Rogers added that only a small percentage of people he works with every day are in the country illegally, but he implies the policy has impacted his department significantly.

"The Ordinance has had a chilling effect on our daily operations. We can no longer call and share information with ICE. They can no longer call and ask for assistance, or ask for intel on suspects involved in criminal activity. This Ordinance has created, in my opinion, a City that is much less safe than it was prior to this Ordinance."

You can read Rogers' entire testimony here.

RELATED: Verify: What does the opioid crisis look like in Colorado?

WHY DENVER?

Rogers will testify in front of the Border Security and Immigration Subcommittee along with a sheriff from Jackson County, Texas, a professor from Stanford University and a representative for the Center for Immigration Studies, a research organization where employees are "animated by a 'low-immigration, pro-immigrant' vision of America."

Republican Congressman Ken Buck, who represents Northern Colorado and Castle Rock, sits on the 13-member subcommittee. Rogers tells Next with Kyle Clark that he called Buck a few months ago to express concerns about Denver's new policy. They have been talking back-and-forth since then, and Buck decided to invite Rogers to testify.

When Next reached out to Denver's Democratic Mayor Michael Hancock Wednesday, his office provided a letter Buck sent to the mayor on Nov. 9. Buck asks Hancock to reconsider Denver's stance and to create an exception for opioid cases.

He writes:

"Many individuals innocently fall into opioid addiction as the result of prolonged pain management to address symptoms from surgery or an accident. These individuals then turn to heroin because their prescription expires or their funds are depleted. Because of its oversupply in America, heroin costs less than prescription drugs. Unfortunately, many of the Schedule I drugs we find in America are produced in foreign countries and then transported here by illegal immigrants."

"As of result of this ordinance, Denver law enforcement authorities cannot communicate with federal immigration officials to determine the immigration status of individuals they detain or arrest on opioid-trafficking-related matters."

You can read the full letter below (click here if it does not appear).

CITY'S RESPONSE

"What he's talking about is specific area of federal law that's civil in nature," Deputy Police Chief Matt Murray told Next. (Go figure - a boss and a union president don't agree.)

Murray also said officers can continue to share information about criminal investigations, like drug crimes, but not about civil matters, e.g. someone's immigration status.

Hancock told Next last month that Denver officers aren't going to figure out someone's status for federal agents. Hancock said the same thing in his response to Buck, in a letter dated Dec. 6. He told the congressman that ICE and the FBI have access to the fingerprints from every individual booked into the Denver County Jail, if they get a warrant.

"To put this discussion in proper context, however, it must be noted that immigrants are less likely to commit crimes than people born in the United States, and it would be empirically inaccurate to suggest that undocumented immigrants commit a disproportionate share of crime. In passing our new ordinance, Denver affirmed our commitment to the ideals of inclusion, acceptance and opportunity. As Mayor, it is my most solemn responsibility to keep all of Denver's people safe, and our ability to protect and serve all people is enhanced when community members feel safe coming forward as either a victim or a witness to crime, regardless of their legal status. Fostering respect and trust between community members and local law enforcement is key in this effort."

Read the mayor's full letter here (click here if it does not appear).

The city sent this official response to the judiciary committee (click here if the letter does not appear).