The Civilian Office of Police Accountability in Chicago is investigating the deaths of London Marquez and Irene Chavez -- two women who died while in police custody over the past two months.
Marquez, 31, died on Jan. 27 while in the custody of 11th District police, COPA said, while Chavez died after an "attempted suicide" on Dec. 18 at the 3rd District Police Station.
The cause and manner of death in both cases are still unknown, pending autopsy results.
Members of Marquez's family gathered on Sunday outside Area 4 Police Headquarters, where she died, and urged the police for answers.
"She was someone who was loved. She has many siblings. She has a mom. She has a dad. You know, we need answers," her sister, Tatoyia Marquez, told reporters.
"People saw her that same day being active, nothing wrong with her, walking around," she added.
They also said that Marquez was seven months pregnant with her first child at the time of her death.
"It's a cold city and it's even colder what happened to my litter sister," her brother, Marquez Marquez, told reporters.
It's unclear why Marquez was put in custody.
A spokesperson for COPA confirmed to ABC News on Monday that the civilian oversight agency is investigating the case, including "why she was arrested."
The Chicago Police Department referred all questions regarding the case to COPA.
COPA announced on Jan. 29 that the agency is investigating an "incident" in which a civilian died while in police custody.
The person was later identified as Marquez.
The cause and manner of her death remain unknown at this time.
A spokesperson for the Cook County Medical Examiner's Officer said that an autopsy was performed on Jan. 28 and COPA was present, but the results are "pending at this time."
COPA is also investigating the death of Chavez, who died in the early hours of Dec. 18, 2021, following a medical emergency related to an attempted suicide.
According to COPA, Chavez was in "critical condition" when she was transported to the University of Chicago Hospital, where she died hours later.
Chavez was arrested after being involved in "an incident" at the Jeffery Pub Tavern, hours before her death, COPA said, but the cause of death is still unknown.
Iris Chavez, Irene's sister, told reporters that police have not provided details surrounding her sister's death and the family is demanding answers.
Iris Chavez started a GoFundMe account to support the family in covering costs related to her sister's death and said that Irene was her only sister.
"When I say my heart is what one would call broken glass in a bag...MY absolute FAVORITE PERSON IN THE WHOLE WIDE WORLD and ONLY SISTER HAS PASSED AWAY," she wrote.
"Irene taught me all things are possible and things aren't always what they seem. To always do deep research and open my mind to ALL sides before I make a blind decision," she added. "I just always have to remember what I find may not be what I want or am even ready for. BUT for MY SISTER I AM GOING THE DISTANCE to find out absolutely every piece of answer I could get Even if it just is what it is! TRUTH...TRUTH AND ANSWERS IS ALL I SEEK."
A spokesperson for the Cook County Medical Examiner's Officer told ABC News that an autopsy was performed on Dec. 18, 2021 and COPA was present, but the cause and manner of death are "pending at this time."
Last month, COPA announced that it obtained video and other materials related to Chavez's death and said that the civilian oversight agency plans on releasing the materials within 60 days of the incident "as part of COPA's continued commitment to transparency."
COPA told ABC News on Monday that the agency will "work in coordination with the family and their representative" in releasing the materials, but did not provide a date.
"This is the second incident in Chicago in regards to our Black and brown community -- are arrested and brought in custody one way, but leave in a body bag," Rabbi Michael Ben Yosef of the Chicago Activist Coalition For Justice told reporters on Sunday.
The Chicago Police Department has referred questions regarding both cases to COPA.