About 20 migrants were detained and processed by immigration authorities Friday on a flight that was due to leave for Killeen, according to a source familiar with the incident.

Border Patrol agents and troopers with the Texas Department of Public Safety were seen inspecting a private plane Friday morning at McCreery Aviation Co. near the McAllen International Airport.

Bags of roughly 20 cell phones were also seen in the hands of an agent who walked out of McCreery Aviation, seized from the individuals who were taken into custody.

A Beechcraft 1900 aircraft was stationed outside the hangar. The plane had arrived from Killeen just after 10 a.m., and due back in the city just after 4 p.m. according to a flight plan posted on Flightaware.com.

The type of aircraft appeared to be a twin-prop model with 19 seats.

Friday's incident appears to show an emerging trend involving immigration arrests and private aircraft. It's the third such incident in three weeks.

On August 31, 12 immigrants were detained at the South Texas International Airport at Edinburg chartering a plane to Houston.

Nine immigrants were also arrested for attempting to charter a private plane on September 7 at McCreery Aviation, where Friday's incident happened.

Channel 5 News reached out to Homeland Security Investigations who released the following statement:

“HSI is aware of the situation and is assessing the enforcement action. No additional details are available at this time," a spokesperson said.