Beginning on Monday, May 15, Theresa Lockhart called in sick to work at Schoolcraft High School in Michigan, where she taught Spanish. She called in sick — again — on Tuesday and Wednesday of that week.
But there was no call on that Thursday, and Theresa didn’t show up for work. It was the same the next day.
“That was disconcerting to us,” Rusty Stitt, the superintendent of Schoolcraft Community Schools, tells PEOPLE.
On that Saturday, Lockhart’s colleagues traveled to her home in nearby Portage, Michigan. There they spoke with her husband, Christopher Lockhart, who allegedly told them that she wasn’t home but that he would call authorities if she didn’t turn up by the following Monday.
“That just didn’t jibe with me,” Stitt says. “So I made the call on Saturday.” His call, on May 20, was when Theresa was officially reported missing.
Weeks later and there has still been no sign of her. Authorities have searched for the 44-year-old on the ground and in the air, including in a nearby body of water, with no luck. They discovered her vehicle near a Park and Ride a few miles from her home.
She was last seen leaving a local fitness center about 5 p.m. on May 18.
The focus has now shifted to include the possibility that she is dead, Portage police tell PEOPLE. Christopher, her husband — who did not return a message seeking comment — has been named as a person of interest in the case.
“He hasn’t cooperated pretty much from the beginning — very little, if any,” says Senior Deputy Chief John Blue with the Portage Department of Public Safety.
Theresa’s sister said much the same, telling The Huffington Post, “He wasn’t very forthcoming with information. To be truthful, he seemed rather lackadaisical in his attitude … definitely not the attitude of a loving husband whose wife is missing.” (Theresa’s family did not return a call for comment.)
On June 7, police obtained a warrant to search the Lockharts’ home, according to a news release.
“Our priority from the start is to locate Theresa,” Blue tells PEOPLE. “We have to rule everything out first, that she’s not at another location or in another country or anything like that. As the time progresses, it affirms up more to the fact that she’s deceased and we’re looking at all the different elements with regards to if it’s a possible homicide.”
Their investigation is ongoing as Theresa’s community continues to search and pray.
“There’s not a day that goes by that we don’t think about her,” Stitt says. “We’re still optimistic and hopeful here.”