(NewsNation) — A U.S. Border Patrol chief is calling the discovery of a child dosed with sleep aids by a human trafficker in El Centro, California, “criminal actions so horrendous they defy human decency.”

The traffickers allegedly drugged the child to prevent them from talking to agents at the border, just one instance of the dangerous tactics being used to exploit children at the U.S.-Mexico border.

According to federal fact sheets, traffickers often target unaccompanied minors and vulnerable families, knowing that the children have no way to protect themselves. And authorities believe this tactic of sedating children is a way of making sure the children are seen, but not heard, by border authorities.

Multiple reports of these druggings have come to light in recent weeks.

In Arizona, U.S. Customs and Border Protection (CBP) officers at the San Luis Port of Entry intercepted a woman attempting to smuggle two children across the border on Aug. 29.

The children, aged 8 and 11, had also been sedated. The woman, an American citizen, presented birth certificates that didn’t belong to the children. The suspect was arrested and the children were turned over to authorities.

And in Laredo, Texas, a 23-year-old woman has pleaded guilty to smuggling a toddler across the border, sedating her with melatonin gummies and using a fraudulent birth certificate just days ago. That suspect was part of a child smuggling operation that targeted young children under 5 years old.

Members of the smuggling ring pretended to be related to the children when crossing the border, a common tactic.

A recent House Subcommittee on National Security, the Border, and Foreign Affairs report said that as many as three in 10 children had no familial relationship whatsoever to the adults that claimed them.

During the Trump administration, DNA testing was used to verify familial relationships at the border, in an effort to crack down on smugglers posing as family members.

While the DNA testing program ended during the Biden administration, some tests are still being conducted for specific age groups of migrants during their appointments with CBP One.