A Utah mom has revealed details of the harrowing moments she realized her children’s father allegedly took them to Mexico, triggering an AMBER alert.

Lizzie Tomich reported 22-month-old Will Richman and 10-month-old Wesley Richman missing in Saratoga Springs, Utah on Saturday, May 23, the Saratoga Springs Police Department confirms to PEOPLE; this was a week after the children were last seen with their father in Shelton, Wash., Tomich wrote in a Facebook post this week.

An AMBER alert issued by the Utah Department of Public Safety over the weekend said the children were in “imminent danger of serious bodily harm or death,” and named their father, 46-year-old Dane Stephen Richman, a suspect.

The children were located safely in the northwestern Mexican city of San Felipe on Tuesday, May 26, Saratoga Springs police said in an update, which was shared online by the FBI.

Tomich grew concerned when Dane allegedly did not show up for a deposition on Friday morning and did not respond to her calls or texts, FOX 13 previously reported. Saratoga Springs police declined to confirm this information when contacted by PEOPLE.

Tomich then requested a welfare check, leading police to his residence which was empty, triggering alarm bells for the family, the outlet reported.

“When we learned this, we knew something was wrong,” Tomich said, according to FOX 13.

At one point during the ordeal, Tomich reportedly said, Dane responded to her text messages, claiming he had taken the boys camping.

It wasn’t immediately clear when in the timeline of events this exchange occurred, but FOX 13 reported police believe that Dane sent this message when he was near San Diego and had already crossed the U.S.-Mexico border.

Since the children’s safe return, a family member has opened up about their relief and gratitude.

“We will appreciate every day from this day forward. I have never experienced true terror to my family before this,” Jenny Hirsch Tomich wrote on Facebook on Wednesday morning.

“The thought of those two little guys to never be seen again was more than any of us could even process. Lizzie was so incredibly brave but losing herself more and more from the heartache she was feeling,” Jenny wrote, adding that they were waiting to celebrate with the boys as soon as they get back home.

A motive behind the alleged disappearances was not immediately clear. Police previously said Dane was “severely depressed” and had sold his belongings and abandoned his home before allegedly taking the kids.

Dane has since been arrested on two counts of custodial interference, Saratoga police said in their statement this week. It was not immediately clear if he has denied the allegations or retained an attorney to speak on his behalf.