The parents of an 18-year-old Loyola University Chicago freshman who was fatally shot last month are speaking publicly for the first time, describing the death of their daughter, Sheridan Gorman, as "a preventable murder." They are also demanding accountability for why the suspect, an undocumented immigrant, was in the United States and out on the street despite a previous arrest.

At around 1:30 a.m. on March 19, Sheridan Gorman was walking with friends along Lake Michigan, hoping to catch a glimpse of the northern lights. The group was about a block and a half from Loyola's campus when Chicago police say she encountered a masked gunman at the end of a pier.

"He, like, moved towards her threateningly," Jessica Gorman, Sheridan's mother, told CBS News, recounting what she'd learned of the events. "She turned around and she warned her friends that there was a man with a gun and you need to run. And they ran."

Thomas Gorman, Sheridan's father, said his daughter made it about 40 feet before she was shot in the back and neck. She died at the scene. Chicago police have said the shooting appeared random. 

"She was a really amazing person, I actually grieve not only the people she touched in this life, but the people she won't touch," Jessica Gorman said. "… No one should have to deal with the police coming to your door at 6 a.m., falling to your knees when you hear the news that no parent should ever hear."

"There's nothing that prepares you for going to the medical examiner's office and filling out the paperwork," Thomas Gorman said. "Your hand is trembling. And then you have to go identify your daughter's body. And they ask you if you're ready, and nothing makes you ready for that."

The family was told her warning likely saved the lives of her friends.

"Presumably, that's what we heard," Jessica Gorman said. "They say it was a senseless tragedy. It wasn't. It was a murder. It was a preventable murder."  

Chicago police arrested 26-year-old Jose Medina on charges including first-degree murder and illegal possession of a firearm in connection with the slaying. Medina has not yet entered a plea and is set to be arraigned next week.

According to the Department of Homeland Security, Medina is a Venezuelan who entered the country illegally in 2023. 

Julie Koehler, a public defender who is Medina's lawyer, said in a statement to CBS News that in 2018, Medina had been robbed at gunpoint in Colombia and was shot in the head. "He survived but lost a portion of his brain and his skull, leaving him with the mental capacity of a child," she said.

Jessica and Thomas Gorman dispute Koehler's assessment.

"He had the mental capacity and the wherewithal to buy a gun, to have a mask on, and to be waiting," Jessica Gorman said. "The mask was on, and he had a gun pointed at my daughter when she passed him."

Added Thomas Gorman, "A child does not do that."

DHS said Medina was first apprehended by U.S. Border Patrol in May 2023 and released into the country under the Biden administration.

A little over a month later, he was caught shoplifting in Chicago, arrested and released again, DHS said. An arrest warrant was issued after he didn't show up to a court hearing.

Jessica Gorman said the couple are "still trying to explore" the policies they believe led up to the shooting.

"Clearly there needs to be some cooperation between state and local government and federal officials," Thomas Gorman said. "When someone commits a crime and they've been here illegally, there needs to be cooperation. He was, you know, he was arrested for, yes, a nonviolent crime, but he also was here illegally. In our mind, he should've been handed over to the feds at that point."

The Trump administration has used Sheridan Gorman's death to push for a tougher stance on immigration.

While her parents say they don't want their daughter's death to be about politics, they do want accountability.

"I don't know what the longevity of this effort takes, but I will never rest," Jessica Gorman said. "And yes, they've awakened a bear. They've awakened a big grizzly mama bear. I got to fight for my child. I have to fight for yours. I have to turn this devastating darkness into light somehow."