Police are treating it as a highly suspicious missing persons case.
ABC7 News talked with Alexis' brother, Gwyn Gabe, for insight into what the family is going through.
"It was like a regular day. She asked if she had mail at the post office," he said.
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That was last Wednesday afternoon, January 26.
Gwyn Gabe said by the next morning his younger sister Alexis Gabe hadn't come home to the apartment she shares with her parents.
He said they knew something was wrong because, "Usually she has responsibilities, she drops my brother off at school."
The family launched an intensive search around Brentwood and Oakley.
That afternoon they found her light blue Infinity abandoned on a residential street, keys still in the car.
Gabe said, "As soon as my parents got there my dad was like, 'open the trunk.' So I unlocked the trunk and opened it up and nothing was there. Nothing there. Yeah that moment, it was harrowing for sure."
Gwyn Gabe's girlfriend Morgan Strenfel is helping in the search for the recent nursing school graduate. Her cellphone is turned off they said, and her personal belongings are gone.
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They reported her missing to police. They contacted her ex boyfriend, someone they say she dated for three years until late 2021. They say he told them he saw her the night she vanished.
"He did say she was there and she left at 9 p.m.," Strenfel said.
They said he has not helped them in the search for Alexis Gabe, but have not asked directly for his assistance either.
They said this week, police executed a search warrant at the ex-boyfriends home in Antioch, removing bags of potential evidence.
They praised police for their efforts and launched their own social media campaign, distributing fliers across the entire Bay Area and beyond.
There is also a GoFundMe page to help fund the search efforts.
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Gabe said, "This doesn't feel real. I'm seeing her poster all over the place and I'm seeing her on the news. My parents from the start we're just extremely worried. It just is getting worse and worse, now a lot more darker thoughts are starting to enter my parent's minds."
Strenfel tearfully added, "I would say support from family and friends has been huge. If we didn't have that I don't know if we'd be able to do this. It's pretty much indescribable. There's no words."
The search continues as police pursue tips and analyze evidence.