How do I draft an office memorandam of law in the following case?

Mark Murry has requested that our office represent him in a Civil Rights matter where he claims he was falsely accused of robbery, was falsely imprisoned, and suffered serious injuries. Please review the following facts of the case, as well as the legal authority that I have provided, to determine the strengths and weaknesses of Mr. Murry's case. Discuss whether you think we have a good case against Detective Rose and whether she had probable cause to believe Mr. Murry was the person who committed the robbery.

FACTS:

Debbie Donnow was robbed by a man she identified as "Scott Murry or Murphy" on January 1, 2020.For the next two days she remained at home crying before she contacted her mental health worker and explained what happened.The police were notified, and on January 4, 2020 Officer Rachel Rose interviewed and took Ms. Donnow's statement

Ms. Donnow claimed that she recognized the man who robbed her because they attended the same mental health facility, Saints Medical Center, and that she knew his name because "...they would call it out.It's"Scott Murry or Murphy."Along with that name, she also provided Officer Rose the alleged robber's height, weight, age, treating doctor, and eye color.

Later that month, Ms. Donnow was admitted to a psychiatric unit where she was diagnosed with schizophrenia and treated until her release on February 16, 2020.While hospitalized, she met her current boyfriend, Carlos Wright, a fellow patient with a history of drug and alcohol abuse.On March 17, 2020, Ms. Donnow, and Carlos Wright got into a fist fight with "Scott Murry or Murphy" at a local bar.The police were called but were unable to apprehend Murry/Murphy; however, Ms. Donnow claimed to have secured the plate number from Murry/Murphy's vehicle, which Officer Rose then ran with negative results.

On May 15, 2020, Ms. Donnow and her boyfriend made it to the Detective Unit to view photos to look for the assailant.Officer Rose showed them a computer photo array of all Murrys and Murphys in the police database, eight pictures total.Ms. Donnow pointed to a picture and said, "that's him."Officer Rose printed the photos without asking, "Are you positive?"Mr. Wright then viewed the same photos and said, "That resembles his smug smile."Both Donnow and Wright signed the photo without being told that the person in the photo would be arrested.

On May 18, 2020, the positive photo ID by the victim and her boyfriend was the basis for Officer Rose's probable cause to have an arrest warrant lodged against Mark Murry, the individual in the photo.The Affidavit of Probable Cause contains a "positive" identification by Donnow but not a "positive" identification by Carlos Wright.

Mark Murry was arrested and charged with robbery on May 30, 2020.That afternoon, members of City Police Department converged on him in public, exhibited guns, forced him to the ground, handcuffed him behind his back, and advised him that he was under arrest.Murry was embarrassed because he was arrested in front of several neighbors and was transported to the City Police Department where he was processed.

After arraignment, Mr. Murry was imprisoned for 30 days in the City's holding facility awaiting trial as no one in his wealthy family would bail him out.During this time, he was incarcerated in a section of the prison designated for the most violent offenders where he was continually terrorized, ridiculed, and tormented by other inmates.

Suspecting a potential problem with Ms. Donnow's testimony, Assistant District Attorney Karson wanted a line-up because during a phone interview, Ms. Donnow denied making a "positive identification" and told Officer Rose, "That looks like him." Two days later, at a lineup identification at the prison, Ms. Donnow failed to identify Mr. Murry as her assailant and screamed, "He is still out there (meaning on the street)."

The City District Attorney's Office subsequently withdrew prosecution against Mark Murry.