Updated Oct. 24: Revised to include new information on the search and candlelight vigil.

Zuzu Verk (Facebook)

While authorities continue to search for clues in the disappearance of a 22-year-old woman in West Texas, friends and family held a candlelight vigil in Keller.

Zuzu Renee Verk, who has ties to North Texas, is a student and employee at Sul Ross State University. She was last heard from Oct. 12, Alpine police said.

The reward for information leading to her location or safe return was raised Friday to $100,000.

Verk's mother, Lori Verk, said in a Facebook post Sunday that they "need a miracle."

Alpine police have asked for help identifying the movements and locations of several vehicles during the early morning hours of Oct. 12 and Oct. 13.

Police said over the weekend that they are looking for anyone who may have seen a white 2016 Ford Mustang and a 2005 Ford F-150 with magnetic decals for U Construction, though the decals may have been removed.

Evidence from the carpet of the Mustang, which is in police custody, was sent to a forensic lab in El Paso for analysis, CBS 7 reported.

Police are also looking for more information on the whereabouts of a gray 2006 Jeep Liberty and a 2004 Mazda Miata convertible with a beige top between midnight Oct. 12 and the morning hours of Oct. 13.

The Brewster County sheriff's office has asked area ranchers and landowners to check their property for "any suspicious signs of disturbed earth, personal items on the ground, anything that might raise your suspicions that it may need to be investigated further."

1 / 5Law-enforcement officials continue the search for Zuzu Verk at the North Brewster County Emergency Response Center on Friday. (Brewster County Sheriff's Office) 2 / 5The gray truck police are asking for information about.(Alpine Police Department) 3 / 5White Mustang police have in their possession that they are asking for information about.(Alpine Police Department) 4 / 52006 Jeep Liberty police are asking for information about.(Alpine Police Department) 5 / 52004 Mazda Miata convertible police are asking for more information about. (Alpine Police Department)

Investigators have also combed through hundreds of hours of surveillance video and are looking for more.

Boyfriend not cooperating

Lori Verk told KOSA-TV that Zuzu Verk and her on-again, off-again boyfriend went to the movies Oct. 11 with friends. She did not show up for work or a midterm Oct. 12.

At a news conference Friday, Alpine Police Chief Russell Scown said that the boyfriend — whom he did not name — has hired a lawyer and won't speak with police.

"Unfortunately we have one individual who we believe does have information, who has refused to come in and talk to us, has retained an attorney, and we haven't heard a word from him," Scown said. "So, when you talk about all the hundreds of people from all over the state that are working actively to help solve this and bring Zuzu back to her family, and one individual that won't … that ought to tell you something."

Verk's father, Glenn Verk, pleaded with the boyfriend to come forward during the news conference.

"If you would please come and cooperate with the police department and help us and help them I know that you love her — I hope that you do," he said.

Search efforts

Volunteers and search crews have been looking for Verk, whose family lives in Keller. Teams have searched more than 200 square miles, both by foot and by air, Alpine police said.

On Monday, the search was expanded into neighboring counties and a drone was being used to scan Brewster and Presidio counties.

Several agencies have been assisting in the search, including Texas Equusearch, the National Park Service, Texas Forest Service, U.S. Customs and Border Protection, and CBP Air & Marine.

Brewster County officials have also searched an apartment near campus for evidence.

Sul Ross President Bill Kibler issued a statement on Verk's disappearance, pledging the university's continuing support and participation in the search.

"During the past week, the uncertainty associated with the unknown has pervaded the usually-peaceful and safe environment the Sul Ross State University family enjoys," Kibler said in a written statement. "The disappearance of one of our students, Zuzu Verk, has deeply affected the entire campus community as well as Alpine and the surrounding area."

Zuzu Verk attended Timber Creek High School in Keller ISD, WFAA-TV (Channel 8) reported.

A candlelight vigil was held Monday night at Bear Creek Park in Keller.

Verk is 5 feet tall and weighs about 110 pounds. She has short dyed blond hair and hazel eyes.

A GoFundMe has been set up to help the Verk family with expenses while the search continues.

Anyone with information is asked to call Alpine police at 432-837-3486 or the Brewster County Sheriff's Department at 432-837-5541.