(CNN) -- As Tracy Ocasio's 28th birthday came and went last week, her mother remained hopeful that she would soon get answers about the young Florida woman's disappearance nearly three months ago.
Tracy Ocasio disappeared after watching a ball game with friends at an Orlando, Florida, sports bar.
Police have a person of interest in custody on unrelated charges, but they still don't have the full story, said Detective Mark Olson of the Ocoee Police Department near Orlando.
In honor of Ocasio's birthday, her family increased the reward for information on her disappearance to $20,000.
Elizabeth Ocasio said she last spoke with her daughter about 8:30 p.m. May 26. Tracy Ocasio said she planned to come home that night after watching a televised basketball game with friends at the Florida Tap Room, a popular sports bar in Orlando.
When Ocasio didn't come home that night, her mother said she assumed she'd decided to stay at a friend's house. She often stayed with the friend when she was too tired to drive home.
At 6:30 the next morning, Elizabeth Ocasio sent a text message to her daughter: "Where are you?" She did not receive a response, she said, so she called her daughter's cell phone again two hours later. The phone rang a few times and then went to voice mail. She tried calling Ocasio several more times that day, and each time, the call went to voice mail.
"I was worried, but I still did not imagine that anything terrible could have happened," Elizabeth Ocasio said.
Panic set in when she received a call from police on the afternoon of May 27. They'd found Tracy Ocasio's car in a rundown neighborhood three miles from the Ocasio home. The car was parked on private property, and the residents had called to have it towed.
"When I got there, I knew something didn't make sense. Tracy would never go to such a neighborhood by herself," Elizabeth Ocasio told CNN. She found her daughter's purse in the car, but her ID, cell phone and car keys were missing.
By 7 p.m., Tracy Ocasio was officially reported missing and a county-wide search was under way. It lasted for weeks. "We searched bodies of water and heavily wooded areas," Olson said, "and we continue to search based on tips we receive."
The investigation led detectives to James Hataway, 28, who is considered a person of interest because a Tap Room surveillance video shows him leaving the bar with Tracy Ocasio, Olson said. A spokesman said the Orange County Public Defender's Office would have no comment.
Police questioned Hataway for 11 hours over two days. He told investigators that Ocasio had given him a ride home from the bar that night, Olson said.
Hataway told police that he didn't see Ocasio after she dropped him off. His home was just 200 yards from where Ocasio's car was found, police said. During questioning, Hataway took a polygraph test, which police said showed some discrepancies, Olson said.
Police brought bloodhounds to where Ocasio's car was found, but the dogs didn't hit on her scent, leading police to believe she wasn't the one who parked her car there. Police also say no forensic evidence was found to suggest Ocasio was injured or killed inside her car.
Police are holding Hataway on unrelated charges at the Orange County Jail. He is charged with aggravated battery, robbery and false imprisonment stemming from an incident in neighboring Seminole County in August 2008.
A young woman said she gave him a ride home one night. She said he attacked her and tried to break her neck, but she fought back. She'd reported the assault when it happened but only later were police able to identify Hataway as the alleged assailant. Hataway remains in custody on those charges with bail set at $250,000. He has not pled.
Shortly after his interrogation in the Ocasio case, the public defender's office took Hataway's case, and he stopped talking.
Hataway has not been named a suspect and has not been charged in the Ocasio case.
Police and family urge anyone with information that can lead to the arrest of the person responsible for Ocasio's disappearance to call the tip line at 1-800-423-TIPS. A $20,000 reward is offered.