All seemed normal for Dalton Jack and his girlfriend, Mollie Tibbetts, until last Wednesday night.
Jack reportedly last saw her two days earlier, on July 16, in Brooklyn, Iowa, where they both live. He headed the next day to Dubuque, Iowa, for work, some two hours away, according to ABC News.
Tibbetts, a 20-year-old rising sophomore at the University of Iowa, stayed behind in Brooklyn at Jack’s house, to dog-sit, he told ABC.
On Wednesday evening, authorities say she was seen running around town, like she normally did. She messaged someone around 7 p.m., local TV station WOI reports, and around 10 o’clock that night, Jack opened a picture from her on Snapchat — a selfie that seemed to be sent from inside, with a caption — though it’s unclear when the message was sent.
Tibbetts has seemingly not been heard from again.
Six days later, her disappearance remains a mystery with many questions and no answers, even with the ramping up of a nationwide campaign — both on the ground and online — to find her. Local authorities are stymied as to why and how she could have gone missing from her rural community of about 1,500 people and who may be responsible.
Her wallet and ID were left behind at the house where she was dog-sitting, according to ABC News.
Detectives are still trying to determine for certain if she “disappeared while jogging or if she left from the house afterwards,” Poweshiek County Sheriff Thomas Kriegel told PEOPLE on Monday morning.
“The run happened and then she was at the house as far as we know. I don’t think she would’ve run in the dark,” her aunt Kim Calderwood told local station KCRG.
“At this point,” Kriegel said on Monday, “everything is being considered — we are looking at everything and everybody.”
Jack, however, is certain of this: “This is not like her,” he told WOI of Tibbetts, whom he has reportedly been dating for nearly three years after they met in high school.
“If this is her running off, nobody would’ve seen it coming,” Jack said. “Nobody in the world. Not her family, not me — nobody would’ve ever guessed that she just take off and not tell anybody.”
He said he believes Tibbetts is out there, somewhere, and that she will be found safe and returned home, according to WOI.
“She goes for a run every night,” he told ABC News on Monday. “She likes to go whenever the sun’s not down, but it’s starting cool off, like 6 or 7. She knows Brooklyn extremely well, better than I do and I’ve lived here my entire life.”
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Speaking with WOI, Jack said he first learned Tibbetts had vanished on Thursday afternoon, when one of her coworkers called and said she “had not called into work that day and she hadn’t showed up.” He’d texted her that morning but got no response, according to KCRG.
“And then I looked at the messages and she hadn’t opened or read the message,” he recalled to WOI. “And then I started getting in contact with her friends and family, saying, ‘Have you seen her or heard from her?’ And they all said the same thing: ‘No, we haven’t heard from her since yesterday.’ “
Tibbetts’ family reported her missing on Thursday.
According to WOI, Jack quickly returned to Brooklyn to join the search efforts: “I came home as soon as her mom said that she called the hospital and she wasn’t there.” On Friday, more than 200 people swept the area, hoping to find her.
“She’s the sweetest, kindest most caring person that I’ve ever met in my life,” Jack told WOI. (PEOPLE’s attempts to reach him directly were not immediately successful.)
“I’ve never seen her do anything like an act to hurt anybody ever,” he said, “and I’ve known her for three years and I spend pretty much ever day with her.”
Laura Calderwood, Tibbetts’ mother, told ABC News that Tibbetts had planned to fly out for the upcoming wedding of her boyfriend’s brother, scheduled for early August in the Dominican Republic.
“As that date gets closer, it’s like closing in on me, because I’m thinking about these two people that are getting married that were also really close to Mollie,” Calderwood said. “[It’s] supposed to be the happiest day of their life.”
She said she did not have words “to describe how you feel when you don’t know where or how your child is.”
While searches have so far been fruitless, Tibbetts’ loved ones are steadfast in their efforts to solve her disappearance.
The sheriff said Monday that authorities were reviewing the case and plotting their next moves.
Said cousin Emily Heaston: “We know Mollie wants to be home.”
“All we can do is raise awareness,” Alyssa King, who has known Tibbetts for years, told PEOPLE, “and we’re working as hard as we can to spread the word.”
Tibbetts is described as 5-foot-3-inches tall, weighing about 120 lbs., with long brown hair and brown eyes. Those with any information about her whereabouts are urged to email investigators at email@example.com or call 641-623-5679.