The family of Lauren Smith-Fields said they are fighting for justice and demanding answers after their daughter was found dead on her apartment room floor shortly after meeting a man on a dating app.

The Connecticut chief medical examiner's office on Monday announced that Smith-Fields' cause of death was "acute intoxication due to the combined effects of fentanyl, promethazine, hydroxyzine and alcohol." The medical examiner ruled the manner of death an "accident."

But in a legal notice filed Friday as part of a planned lawsuit against the city of Bridgeport, Connecticut, and the Bridgeport Police Department, Smith-Fields' family alleged that police haven’t properly investigated her death and claimed the department has violated their civil rights.

"Lauren Smith-Fields wasn't given the treatment that she should have been given," Darnell Crosland, the family’s attorney, said in an interview with Good Morning America.

Bridgeport police responded to Smith-Fields' home just after 6:30 a.m. on Dec. 12 and found her "lying on her back, on the floor" of her apartment, according to the police report. She "did not appear to be breathing," the report stated.

The man who called 911 told police officers he met Smith-Fields on a dating app three days prior, according to the police report, and this had been their first time meeting.

The man told police they were taking tequila shots before Smith-Fields got sick in the bathroom. He said she went outside briefly, and when she came back in, she went to the bathroom for 10 to 15 minutes, the police report stated.

The man said they continued drinking, and soon they both fell asleep, the report said. He told police that at 3 a.m. he got up and heard her snoring. He woke up later that morning, he said, and saw that blood was coming out her nose and she wasn't breathing.

In the report, officers described the man as "frantic" when he answered the door, adding he was "trembling and visibly shaken."

Smith-Fields' family is now planning to sue the city of Bridgeport and the police department, claiming in the filed legal notice that police "failed to implement the proper crime scene investigation team to collect physical evidence" and "refuse to view the last person to see Smith-Fields before she died as a person of interest."

"You expect the police to follow protocol, which is to question the gentleman that was at the scene, take his DNA, compare it to the physical evidence that's present," Crosland said.

In a statement released earlier this month, the city of Bridgeport said the police department "takes these concerns very seriously" and added, "The command staff of the detective bureau is reviewing the handling of this case to ensure that best practices were and are being followed."

This weekend, Smith-Fields’ family and hundreds of others marched through Bridgeport on what would’ve been her 24th birthday.

Her family said the march was not only to honor her, but also to seek justice. They alleged that they have been neglected and mistreated by the police department and are still seeking answers regarding their daughter's death.

"The way they handled her investigation was literally disgraceful, disgusting, horrible. It was not even human," Lakeem Jetter, Smith-Fields' brother, said in an interview with "Good Morning America."

"I just could not believe that my little, my baby sister was gone," Jetter said. "This loss is so devastating to us. I never lost a sibling before. My mother has never lost a child before."