SAN DIEGO – The ACLU is calling on the Department of Justice to investigate the San Diego Police Department's use of force against those with mental illnesses.

The letter, sent Wednesday, specifically cites fives cases, including the fatal shooting of Fridoon Rawshan Nehad on April 30, 2015, in the Midway District. Nehad was an unarmed, homeless man.

"A series of incidents raises serious concerns that SDPD has a pattern or practice of violating the fundamental rights of people with mental illness or experiencing a mental health crisis," the letter reads. "These encounters are marked by the questionable use of lethal force in incidents that officers may have unnecessarily escalated. The incidents suggest that the SDPD has made an insufficient effort to supply necessary training and resources for responding to matters involving the mentally ill."

The ACLU argues that in several cases, officers used lethal forces "within only minutes of arriving at the scene."

RELATED: FBI will be part of local law enforcement shooting reviews

The ACLU wants the DOJ to examine specific questions, including: "Why the police initiated or escalated the confrontations? Why officers perceived a threat from certain individuals? Whether officers are properly trained in de-escalation tactics?"

In December, the FBI reported that it was investigating the Nehad shooting. In January, the FBI and the U.S. Attorney's office announced that they would have their officials attend briefings on any officer-involved shooting that takes place in San Diego.

Local law enforcement agencies are required to meet with the San Diego County District Attorney's Office within three business days of an officer-involved shooting.

RELATED: Team 10: FBI reviewing deadly officer-involved shooting in Midway District

On Wednesday, following the ACLU's announcement, Benny Roshan wiped away tears as she spoke about the 5-month old nephew her brother never got to meet. Nehad died before his sister could tell him she was pregnant.

"He took his last painful breaths not knowing about it," Roshan told Team 10.

Roshan called her brother's death a nightmare that she and her family will never wake up from.

"It just doesn't make any sense," she said.

Roshan told Team 10 she was devastated when San Diego County District Attorney Bonnie Dumanis said SDPD Officer Neal Browder was justified when he pulled the trigger.

"For the announcement to come out that there absolutely isn't a consequence and that this officer did nothing wrong, it's just like pouring the most vile acid on a really deep gash of a wound," she said.

Roshan said she and her family fully support the efforts of the ACLU and civil rights organizations to have the DOJ investigate how SDPD officers handle people with mental illness, like her brother.

"It gives me a little bit of hope that maybe this issue will be taken seriously and looked at by an independent body … My sincerest hope is that my brother's unfortunate death is the last one," Roshan said.

Early Wednesday evening, SDPD Chief Shelley Zimmermann issued the following statement in response to the ACLU's request for a DOJ investigation:

"No police officer comes to work wanting to be involved in a shooting. Our training strategy focuses on de-escalating situations and deploying the appropriate resources to safely resolve an unstable situation. San Diego Police Officers responded to over 18,000 mental health calls for service last year alone. This is a 100% increase in the last seven years. Public safety is a shared responsibility. The rising mental health crisis facing society today demands the attention of more than just those families who are dealing with mental illness of a loved one. We welcome the opportunity to work together to assist those who are suffering from mental illness."

Other cases cited by the signatories of the letter include the officer-involved shootings of:

-- Philip McMahon, 27, who allegedly charged police in the nude and tried to take away an officer's gun after breaking a neighbor's window in Mira Mesa on Feb. 16, 2015

-- Ja Ma Lo Day, 21, a Burmese refugee who reportedly threatened to kill family members at their City Heights home and then attacked a police dog with a machete on July 13, 2014

-- Nathan Manning, 31, who allegedly attacked a detective who was trying to break up a fight between Manning and his roommate at a Normal Heights intersection on May 20, 2010

-- Bradford Sarten, 55, who allegedly advanced on officers with a kitchen knife after assaulting his 85-year-old mother at their North Park home on April 26, 2010

All the suspects except McMahon died of their gunshot wounds.

Along with Norma Chavez-Peterson, executive director of the ACLU of San Diego and Imperial Counties, representatives of the following agencies signed on to the letter to the Justice Department:

-- A New PATH (Parents for Addiction Treatment & Healing)

-- Alliance of Californians for Community Empowerment San Diego

-- Alliance San Diego

-- American Federation of Teachers, Local 1931

-- American Friends Service Committee

-- Amity Foundation

-- Center on Policy Initiatives

-- Council on American-Islamic Relations, San Diego

-- Employee Rights Center

-- Iredale and Yoo, APC

-- Jewish Family Service of San Diego

-- Law Offices of Joseph M. McMullen

-- Law Office of Thomas E. Robertson

-- NAACP San Diego

-- National Asian Pacific American Women's Forum

-- Partners for Progress San Diego

-- Partnership for the Advancement of New Americans

-- Pillars of the Community

-- San Diego and Imperial Counties Labor Council

-- San Diego Area Black Health Associates

-- San Diego Area Congregations for Change

-- San Diego La Raza Lawyers Association

-- SEIU Local 221

-- Singleton Law Firm, APC

-- Interfaith Center for Worker Justice

-- Urban League of San Diego County