(Photo : Oklahoma State Bureau of Investigation)
Oklahoma State Bureau of Investigation is investigating the suspicious disappearance of 27-year-old Veronica Butler and 39-year-old Jilian Kelley.

Police are urging family and friends of a missing Kansas mom and a preacher's wife to stay quiet while they continue their investigation into the women's mysterious disappearance. 

Veronica Butler, 27, and Jillian Kelley, 39, were traveling from their hometown of Hugoton, Kansas, to pick up Butler's kids in rural Oklahoma when they vanished. It's unclear when they left, but police found their abandoned vehicle on the side of the road in Elkhart, Kansas – about 30 miles outside of Hugoton – Saturday, according to the Oklahoma State Bureau of Investigation.

Authorities have revealed very little details surrounding the circumstances of the women's disappearance, but loved ones said they have been ordered to stay tight-lipped to protect the investigation. 

On Tuesday, an unidentified family member of one of the missing moms told NewsNation authorities instructed them to decline media interviews for the time being.

That same source also said Kelley – the wife of a pastor – may have been accompanying Butler, who was reportedly in the middle of a custody battle with her ex, to act as a mediator when picking up her kids, according to the outlet. 

Butler's children may have been living with their paternal grandmother at the time.

"As of right now, as the investigation continues and we were requested, we're unsure where these women are or what happened to them," OSBI spokesperson Hunter Mckee, previously told NewsNation. "That unknown is what has created it suspicious for us at this time."

Meantime, the Yarborough School – located in close proximity to where the women disappeared and also where Butler graduated from in 2015 – began operating in lockdown mode Tuesday, due to "so many unanswered questions" involving the case, the superintendent wrote in a letter to parents, according to KSN-TV. Additional security will also patrol the campus as the investigation continues.