Updated

The father of a missing Texas college student is pleading for her boyfriend to cooperate with investigators, while police said they've seized a "key piece" of evidence in the case.

Zuzu Verk, a 22-year-old student at Sul Ross State University in Alpine, Texas, was last heard from in the early hours of Oct. 12 after a night out with friends and her boyfriend. With the assistance of the the Texas Rangers and FBI, authorities have launched a massive search for Verk, scouring 200 square miles by air and land.

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Verk's father, Glenn, told FoxNews.com Monday that the young woman's boyfriend -- whom he did not name -- has not cooperated with police and the family.

"When someone you care about is missing, don’t you help?" said Verk, whose lives seven hours away in Keller, the Dallas-Fort Worth suburb where his daughter grew up.

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Verk 6

This white 2016 Ford Mustang has been identified by police as a "key piece of evidence" in the case. (Alpine Police Department)

Verk pickup truck

Detectives are also examining this 2005 Ford F-150 in their search for Verk.

"I drove all night as soon as I heard Zuzu was missing, and when I got there, a search was already in progress," he said. "Everyone wanted to help, but he [Verk's boyfriend] wasn't there."

The Alpine Police Department posted a photo Sunday of a white 2016 Ford Mustang it said is a "key piece of evidence" in the disappearance of Verk, who is considerd a "possibly endangered" missing person.

Photos of the car were posted on the department's Facebook page after authorities said they were conducting a forensic exam on another vehicle -- a grey 2005 Ford F-150.

Investigators are asking people in the area if they saw the vehicles on the road in the early morning hours around Alpine, a small idyllic town about 100 miles from the Mexican border. They are also poring over "hundreds of hours" of surveillance footage obtained by businesses and private residents in their investigation.

The Brewster County Sheriff's Office asked ranchers last week to inspect their properties 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."

Authorities said Friday they had a "person of interest" in the case but declined to give further details. Verk's boyfriend, who has not been named publicly, has retained an attorney.

Glenn Verk, meanwhile, is pleading for the young man to come forward with any information about his daughter's whereabouts.

"We’re calling out to those few who the police say have not been cooperative," he told FoxNews.com.

Verk is described as 5 feet tall, weighing 110 pounds with blonde hair and hazel eyes. A $50,000 reward is being offered for her safe return.

Alpine is about 200 miles southeast of El Paso. Anyone with information on the case is urged to call the Alpine Police Department at 432-837-3486.

"She just shines. She loves life," Verk said of his daughter, a biology major. "She has such a network of friends and people who care about her."