After releasing four Bible balloons into North Korea, a South Korean church is worried about a formal police investigation into the launching.

A few times each year, the church released the balloons to travel across the border. These balloons are tracked using GPS transmitters by ministry staff.

The balloon release is designed to help provide people with Bibles in North Korea, Mission Network News reports.

Paster Eric Foley says a formal investigation was called into the four groups in the country that participate in the launching. Three of the groups launch balloons with political information; Voice of the Martyrs (VOM) Korea launches their balloons with Bibles.

"According to the governor, we’re guilty of fraud, mismanagement of donations, security risk, [and] possible air traffic violations," Foley says.

"The amazing thing about it is we’ve been doing these launches for 15 years and none of these things [were] problems or issues before."

VOM Korea recently held a press conference to address and refute these allegations by the government and to show their financial transparency.

The allegations stemmed from discussions between the North and South Korean governments.

North Korea has been said to be putting pressure on South Korean officials to "make good" on a 2018 agreement that bans the distribution of items across the border. As a result, authorities are investigating the four groups involved in breaking that agreement.

Foley is upset that their 15-year understanding with the South Korean government seems to have suddenly been forgotten.

"Suddenly, balloon launching has become dangerous and balloon launchers [are] criminals, and we’re considered crazy," he says.

Limitation on freedom of the press in the country is one reason Foley says it is hard to share what is happening during this situation.

Foley says after the investigation into the balloon launching was launched, police raided two ministry workers' headquarters and the homes of leaders.

The ministry office is now under 24-hour-a-day surveillance.

Foley is also confused about the sudden desire to restrict their balloon launching by the government.

"We’ve launched in the most difficult moments in recent inter-Korean conflict history," Foley says. Those instances include Kim Jong II's death and nuclear tensions between the countries in 2015.

"In each of those situations, we had a very cooperative situation with the authorities because they know that we only go out to launch on the 10 to 15 nights a year… and that we launch only Bibles," Foley says.

North Korea is currently the worst country in the world for the persecution of Christians, according to the Open Doors USA World Watch List.