Jessica Gorman testified during a House Judiciary Subcommittee hearing over sanctuary city policies.
Her daughter, Sheridan Gorman, was killed in a shooting at a Rogers Park beach in March.
The alleged gunman, Jose Medina, entered the country illegally in 2023 and had a criminal record.
The mother called on lawmakers to crack down on policies she says allow criminals to stay in this country.
"Explain why cooperation with ICE was too much to ask for but asking our American parents to bury our children is somehow acceptable. As me. I just, I need you to tell me," she said.
Medina has pleaded not guilty to the shooting.
He is due back in court next month.