Friends and family searched all of Saturday for Brissa Romero, dispersing to different wooded areas in Vernon Hills, but there was still no sign of the missing Carpentersville teen.
The 17-year-old's sister said they're heartsick and desperate to find her. The family is offering a $1,000 reward for any information that leads to Brissa's safe return.
"I don't know what else we can do, because we really want the cops to help us out. The majority of the part that we can do is simply coming out, showing her that we are not going to stop looking for her. We are nonstop coming out here. I want to say, my cousin started coming out here at 6:30 to catch the sunrise, so we've been here," said Jocelyn Rubi Romero, Brissa's sister.
Police said Brissa vanished on her way to a holiday party at a bowling alley in Vernon Hills on Monday.
Surveillance video shows her arriving at a cousin's house in Des Plaines on Monday night. From there, relatives said, she went to the holiday party around 7 p.m.
"After around 8, that's when her location stopped reloading and refreshing. So, that's when we started thinking, 'OK, this is out of the ordinary. Let's head out over there,'" Jocelyn said.
Police said a car license plate reader and a ping from one of her devices put her near that location, but investigators said cameras at the business do not show her at the party.
"We have faith that she's alive. We have faith that she's going to come back to us and we just want her back," said Silvia Hauilera, Brissa's aunt. "Join us so that we can find her and bring her back to her parents. Bring her back for Christmas. It's our wish this year that we can just get her back."
Brissa graduated from Barrington High School one year early, and is now a Harper College student. Her family is asking neighbors check their surveillance cameras to see if they caught any glimpse of her.
"We're trying to look for her clothes, for her car, and for anything she might've left for us that might've told us, 'Hey, I was taken,'" Jocelyn said.
The family said it's unlike Brissa to be out of touch for any period of time.
Carpentersville police said digital analysis of Brissa's social media accounts revealed no outgoing activity since Monday.
Brissa is 5 feet tall and weighs 115 pounds. She was driving a gray 2008 Nissan Rogue with Illinois plate CZ 64618.
As an extensive search for Brissa's vehicle continues, police said they identified a sticker on it. The sticker, located to the right of the rear license plate, is of a black coyote.
Authorities asked anyone with information to contact Sgt. Webb with the Carpentersville Police Department at 847-551-3481 or QuadCom Dispatch at 847-428-8784.