LOS ANGELES (AP) — Thieves have been raiding cargo containers aboard trains nearing downtown Los Angeles for months, leaving the tracks blanketed with discarded packages.

CBSLA reported Thursday that the sea of debris left behind included COVID-19 test kits and other items the thieves apparently didn’t think were valuable enough to take.

While CBSLA cameras were on the scene, one person was spotted running off with a container used to hold small packages, and a Union Pacific railroad police officer was spotted pursuing two other people. It's not clear if anyone was arrested.

In a statement to CBSLA, Union Pacific said it's "very concerned" about the cargo thefts and has taken steps to address the problem.

“We have increased the number of Union Pacific special agents on patrol, and we have utilized and explored additional technologies to help us combat this criminal activity," the statement says.

The scene was the same in November, when NBC4 showed thousands of boxes discarded along tracks lined with homeless encampments northeast of downtown in the Lincoln Park area.