Sheriff on vanished Texas realtor case says Hurricane Harvey is 'not the reason she's missing' Houston realtor Crystal McDowell was last seen the Friday before the storm hit.

 -- Authorities in Texas are searching for Houston realtor Crystal McDowell who disappeared as Hurricane Harvey was barreling down on the area.

“We’re chasing a lot of leads,” Chambers County Sheriff Brian Hawthorne told ABC News. “But no, Hurricane Harvey is not the reason Crystal McDowell is missing.”

The 37-year-old mother of two was last seen on home surveillance video footage walking through the living room of her boyfriend’s home and then getting into her car – a black Mercedes Benz sedan – parked in the driveway on Aug. 25.

“That morning, we woke up about around 6:30, we got ready, I jumped in the shower and she got dressed and I remember her coming in and saying, ‘Alright, I’m taking off,’” McDowell’s boyfriend Paul Hargrave told ABC News.

According to Hargrave, McDowell left his house, got into her car and left to go pick up her two children, ages 5 and 8, from her ex-husband, Steve McDowell, who lived 12 minutes away.

“She did send me some text messages … a little after that,” Hargrave said. “She had mentioned that she was going to stay at the house, the ex-husband’s house, with the kids or, depending on traffic and how weather conditions were, she was going to take them out.”

McDowell’s uncle Jeff Walters also heard from her that morning.

“I received a message from her … about a billboard her boyfriend had put up for her,” Walters told ABC News.

Hargrave had put up a billboard advertisement showcasing McDowell as a real estate broker. Hargrave showed ABC News text messages from McDowell showing that she had taken a picture of the billboard and then texted him, “And you are so sweet.” He replied, “I love and I’ll always support you.”

With Hurricane Harvey approaching, Hargrave said he grew concerned when he realized he hadn’t heard from McDowell in a few hours.

“It’s not like Crystal not to reply back very quickly, so I thought that was kind of weird, [thinking] maybe she was with family getting things ready,” he said.

The next day, Aug. 26, Hurricane Harvey slammed into Houston and three days later, on Aug. 29, McDowell’s Mercedes was found in the flooded parking lot of a Motel 6, seven miles from her home. McDowell was nowhere to be found.

“We don’t believe she parked it there,” Sheriff Brian Hawthorne said. “We believe that whoever parked it there had hoped that somebody would take it. They left the car unlocked and they left the keys in the console.”

Hargrave said he’s convinced foul play was involved.

“She wouldn’t just get up and leave her kids,” he said. “She wouldn’t do that so I think something is horribly wrong.”

Former FBI agent and ABC News consultant Brad Garrett said in dealing with missing persons cases, authorities will look at a few different things.

“One is the immediate circle of people around them, an ex-husband, former employee,” Garrett said. “Then you have to come up with a timeline. She apparently was at her boyfriend’s house, and then what can you timeline from the time she left his residence, where did she stop? Do they have video footage of her at a 7-Eleven? Or a drug store or some other location. You then take that and you overlay it with her cell phone records, because typically, real estate agents are on the phone all the time, and so where was she, where did her phone ping, what towers can you put her near?”

According to McDowell’s uncle, she had recently started working with him as a real estate agent and everything was falling into place for her.

“She said herself that she was the happiest she had ever been in her life,” Walters said.

After losing her parents at a young age, Walters said family was the thing most important to McDowell and she very much loved her children.

“There’s no apparent reason why she should have disappeared,” Garrett said. “When you look at someone’s background…have they been depressed, had they talked about harming themselves, had they talked about leaving? I haven’t heard one thing that would suggest any of the above.”

In June, McDowell finalized her divorce with her ex-husband, with whom she had shared custody of their children. Her uncle said McDowell never talked about them fighting, only that they “had their disagreements.”

But, according to Hargrave, McDowell and her ex-husband had been arguing frequently.

“The week that she went missing, there were a lot of arguments, a lot of heated arguments, about various situations going on,” Hargrave said.

ABC News’ requests for comment from Steve McDowell were not responded to.

Now her family is searching for answers and has even hired a private investigator, asking anyone who may have information to come forward.

“We need to solve it,” Walters said. “We need to find out who has done this and they need to be punished.”

Anyone with information on Crystal’s disappearance should contact the Chambers County Sheriff’s Department at 409-267-2500.