As time passes, she says the uncertainty is "unbearable."
Laura Calderwood, mother of Tibbetts, told ABC News there are no words to describe how you feel I do not know where or how your child is.
Tibbetts, who was the middle child in her family, was looking forward to her upcoming second year at the University of Iowa and full of hope.
"She is just such an open-minded, fun, loving life, loving person" her mother said, "She was getting ready to move into her first apartment."
Next month, Tibbetts and her boyfriend were planning an international trip.
"She and her boyfriend Dalton got ready in August to go to the Dominican Republic 2. to attend Dalton's bridal wedding, "said Calderwood," when this date approaches, it's like approaching me, because I think of those two people who marry, including Mollie were very close. [It̵
He said Tibbetts stayed alone in his house and watched his dogs. "She runs every night. She likes to go when the sun has not set, but it's starting to cool like 6 or 7, "he told ABC News Monday." She knows Brooklyn very well, better than me, and I've lived here all my life. " Jack said he thinks Tibbetts wore both her fitness tracker and her phone when she went out.
"She probably has Fitbit because she never takes it off. She uses it for the sleep tracker and for all her runs and everything, "he said," She probably has her cell phone, but it's either dead or dead and we tried to make it obvious and it goes straight to voicemail. "
The couple met in high school and has been together for over two years 19659003] "She's cute, sweet, caring, she'll do anything for everyone," Jack said.
Tibbetts was released on Thursday Missing July 19. The sheriff's office said it was unusual that a search for missing persons would continue in the city for so long.
"We've had missing people before, but usually we find them the same day or a week A few days later, "Poweshiek County sheriff Thomas Kriegel told ABC News on Monday," We've never had one that I can remember for so long. "
In this tight-knit farming community of about 1,500 people, everyone knows everyone, said Kriegel. But the rural area makes the search difficult.
"We're surrounded by arable land – corn and soybeans – at the moment, the corn is probably eight, nine feet high – the only way you can locate it is basically walking every other row," he said. "It's difficult, even the planes that fly over have difficulty looking down the rows of corn."
Crews have searched every road, ditch, and body of water near the city, the sheriff said. On Friday, the authorities also conducted a large-scale search in the areas around Brooklyn – and at least 250 people came out to help.
In addition, a helicopter and a plane flew over the area, and kayakers searched for miles across the small rivers on either side of the city.
Calderwood said her daughter's disappearance "completely upset the whole community". She said she could see the tribute in her eyes.
She remains hopeful and praises the efforts of law enforcement agencies.
The University said her thoughts were with Mollie Tibbettts family and friends.
The University of Iowa oversees the situation and will provide assistance if needed, "tweeted the school on Friday.
Tibbetts is described with long brown hair and brown eyes, stands 5 feet 2 inches high and weighs about 120 pounds
Everyone with information is urged to call the Poweshiek County Sheriff's Office at 641-623-5679.
ABC News & # 39; Amanda McMaster contributed to the report.