In Rose Cobo’s Borough Park home, the walls are plastered with calendars and timelines retracing the steps of her daughter in the weeks before her disappearance.

A cryptic voicemail left on the night 22-year-old Chelsea vanished, a mug shot, and text message conversations with two men and a woman who were with her that night, are all part of a growing evidence shrine in Rose’s kitchen, leading her to believe her daughter may be held against her will.

“Someone out there has to know something,” said Rose, a massage therapist who grew up in Bensonhurst. “Even if this is Chelsea’s choice, someone had to have seen something, somewhere. The girl didn’t get swallowed.”

Two weeks before she went missing on May 7, Chelsea — a doting mother of 10-month-old Christopher — was hospitalized at the psychiatric ward in Coney Island Hospital for postpartum-related depression. A doctor there told Rose that Chelsea was “making friends with bad people.”

Weeks later, while sifting through her daughter’s Facebook messages, Rose learned that Chelsea befriended her roommate at the hospital — a girl named Sabrine with a rap sheet that includes drug dealing, shoplifting, and prostitution, according to Brooklyn District Attorney’s Office records.

Shortly after being discharged from Coney Island Hospital, Chelsea, typically a homebody who checked in with her mom constantly, confessed to Rose that her new friends had given her a drug that caused her to black out, and she agreed to check into a joint drug rehab and psychiatric program at St. John Riverside Hospital in Yonkers on Friday, May 6.

At around 10:30am that morning, she boarded a hospital transportation van at Lutheran Medical Center. Chelsea either never made it to Riverside Hospital, or was released the same day, because she was last seen at Floridita, a restaurant in Sunset Park, early the following morning with a unknown man called “Anthony.”

These days, finding Chelsea has become a full-time job. When she is not caring for Christopher, Rose spends her days scouring escort service listings, handing out fliers, and calling the detectives assigned to her daughter’s case. She says KLAAS Kids Foundation, an organization that aids families of missing children, has been her “lifeline.”

Rose has enlisted two private eyes, including retired NYPD captain Sean Crowley, who successfully tracked down a missing Staten Island girl through his investigative firm CTS Research last year.

Chelsea’s case has been transferred to Missing Persons Squad, but she is too old to be a “runaway,” and most leads have run cold, according to Crowley.

“At this point, they are just going through the motions,” he said. “Our inclination is that she is somewhere, but there hasn’t been any new sightings. The only way we are going to find her is with the public’s help.”

Now 54 days have passed, with no sign of Chelsea, and the family is speaking out. They raised $10,000 for information leading to the young mother and have launched a fundraising page to keep Chelsea’s case in the public’s eye.

“Chelsea knows that I am relentless,” said Rose. “I will not stop, I will not relax, I will not be calm until I know that my beautiful daughter is OK.”

Anyone with information about Chelsea is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477) or 911.