Kevin Winker, investigative operations director for the Iowa Department of Public Safety, said Friday he knows the tight-lipped approach is frustrating for people who are eager to know what happened to 20-year-old Mollie Tibbetts.
But he says investigators will continue to withhold basic details about the case because they believe it gives them the best chance to solve it.
At a news conference, Winker said investigators are confident in their timeline of the night Tibbetts went missing from her small hometown of Brooklyn, Iowa, on July 18.
But again he declined to say whether Tibbetts is believed to have returned home safely from a jog that evening.
TIMELINE: Missing college student Mollie Tibbetts' last known movements
At least 40 individuals and businesses have contributed to a fund for information regarding Tibbetts' whereabouts, Greg Willey, VP of Public Relations for Crime Stoppers Of Central Iowa, announced at a Friday news conference with Tibbetts' friends and family.
"Every day I feel Mollie's presence with me. Sometimes I feel her just sitting on my shoulder," her mom, Laura Calderwood, added. "I don't know that I have the strength in me, and Mollie's lending me her strength. Every day. Every night."
Calderwood believes it's possible that someone took her daughter.
"We believe that Mollie is still alive, and if someone has abducted her, we are pleading with you to please release her," she said.
Tibbetts' boyfriend, Dalton Jack, said that if someone took Mollie, he has a message for them: "Everybody has a Mollie in their life. Imagine if this was you, somebody had taken your Mollie."
"Do the right thing and let her go," he added.
Her father, Rob Tibbetts, said he believes the reward will incentivize someone to come forward. He said he believes there is someone out there who is withholding information, either because they think it's too trivial or because they are worried it will incriminate a loved one.
"Nothing is irrelevant. Nothing is trivial," he said. "If you have nothing to hide, you have nothing to fear. So come forward, share that information with authorities, and let's bring Mollie home."
The Associated Press contributed to this report.