The family of Kate Steinle, who was fatally shot when she was walking along a San Francisco pier in July, plans to file a lawsuit against San Francisco Sheriff Ross Mirkarimi, Immigration and Customs Enforcement and The Bureau of Land Management holding them responsible for her death.

Authorities say Mexican national Francisco Sanchez, an undocumented immigrant who had been arrested and deported previously, shot Steinle in July while she was walking on the Embarcadero with her father. Her death sparked a national debate about San Francisco's controversial sanctuary city policy, which offers special protection for undocumented immigrants.

The Steine family — which includes Kate's parents Jim Steinle and Liz Sullivan and her brother Brad — will be announcing the lawsuit at a press conference on the steps of the San Francisco City Hall Tuesday. They will be joined by their attorneys Frank Pitre, Brian Schnarr and Alison Cordova of Cotchett, Pitre & McCarthy.

Since the death of their daughter, Jim Steinle and Liz Sullivan have become activists demanding justice for their daughter. "Everyone can’t keep saying this is the way it is — it isn’t the way it has to be. We have to stand up and say we’re mad as hell we’re not going to take it anymore,” Sullivan said.

Both want to make sure what happened to their daughter doesn't end up happening to someone else. "Somebody has to stand up and unfortunately it took the death of my daughter to become activists,” Steinle said.

Mirkarimi faced intense criticism in the wake of the shooting because his department had custody of the man charged with the murder of the young woman at the pier and let him go in April without notifying ICE.

On Monday, Mirkarimi's office released a statement, saying that while the sheriff can’t comment on potential litigation, "he continues to extend his deepest sympathy to the Steinle family for their loss.”

Mirkarimi ordered his department to cease all communications with federal immigration authorities regarding requests for notification for "undocumented, convicted felons" back in March.

Sanchez pleaded not guilty to the murder of Kate Steinle. The gun used in the shooting was stolen from a Bureau od Land Management ranger's car in June.

According to immigration officials, Sanchez, a 45-year-old repeat drug offender, was deported five times. He was out on the streets of San Francisco after city officials disregarded a request from immigration authorities to keep him locked up.

Sanchez told television reporters in a jailhouse interview that he decided to come to San Francisco because of its sanctuary city status, which prohibits city employees from helping federal authorities with immigration investigations or arrests unless required by law or warrant. That said, the ordinance does not prohibit local law enforcement from informing ICE that they've arrested someone in the country illegally for a felony offense or who has prior felony convictions. Since the shooting, the sanctuary city policy has been criticized by the likes of Hillary Clinton, Donald Trump and Fox News host Bill O'Reilly.

Mirkarimi has defended his office's decision to release Sanchez, who was in the U.S. illegally. He said that the U.S. Immigration and Customs Enforcement agency should earlier have issued an arrest warrant for Francisco Sanchez.

In response to criticism about the city's sanctuary city policy, Mayor Ed Lee issued a statement saying it was never intended to protect "repeat, serious and violent felons."

Since the shooting, four Bay Area counties — Alameda, Contra Costa, San Mateo and Marin — have agreed to notify ICE when inmates flagged by the agency for possible deportation are about to be released, the Mercury News reported.

Cheryl Hurd and The Associated Press contributed to this report.