The Border Patrol’s practice of detecting but not apprehending illegal immigrants -- known as “Turn Back South” -- is in effect far north of the U.S.-Mexico border, Arizona Sheriff Larry Dever claimed in congressional testimony Tuesday morning.

“It appears, according to numerous reports from current and former border agents, that this practice has gravitated many miles north of the border. That means that, regardless of proximity to the border, people who are detected but not caught are considered to be “Turned Back South,” Dever said in his written testimony before the Homeland Security Subcommittee on Border and Maritime Security.

Last month, FoxNews.com first reported that Dever said he’d been told by Border Patrol officials, including at least one senior supervisor, that they have been ordered to reduce and to sometimes stop arresting people attempting to cross into the U.S. illegally.

Homeland Security officials, including Border Patrol Chief Michael Fisher, have repeatedly denied these claims, but a flood of current and retired Border Patrol agents from across the country continue to come forward with details of their own that support Dever’s initial remarks.

Dever leveled another new charge: That TBS-ing is going on within the American judicial system.

“There are policies in place that establish thresholds for quantities of drugs and numbers of illegal aliens before consideration for prosecution can be entertained. In at least one Federal District in Texas, if you are caught smuggling less than 750 kilos of marijuana, you will not be subjected to prosecution,” Dever wrote, citing several examples.

“TBS occurs at many levels and is quickly assimilated into the understanding of the bad guys on how to game the system.”

Committee Vice Chairman Ben Quayle pressed Dever on prosecutorial smuggling thresholds toward the end of the 90-minute hearing.

Dever responded with a case in which someone in the U.S. illegally had been deported 23 times but never charged.

On Tuesday, during the same hearing, Border Patrol Deputy Chief Ron Vitiello wrote in his testimony:

“While there is still work to be done, every key measure shows we are making significant progress along the Southwest border. Border Patrol apprehensions have decreased 36 percent in the past two years, and are less than a third of what they were at their peak.”

He was not questioned by committee members about TBS-ing, though that was not the focus of the hearing on cooperation between local and federal law enforcement at the border.

After the hearing, Dever told FoxNews.com that he thought the hearing had gone “okay.”

“They could’ve been a little more difficult. They could’ve asked more difficult questions,” Dever said, adding that he’d hoped the committee members would’ve asked more about the TBS part of his submitted testimony.

“That was something that they could’ve delved into, but they didn’t,” he said.

“It was pretty much hands off, it wasn’t a game of hardball.”

The Department of Homeland Security called the notion that border agents have been instructed not to apprehend aliens “completely false.”

“‘Turned Back South’ is not a policy or a tactic employed by the Border Patrol – it’s a designation used for record-keeping purposes when an illegal alien who has just crossed the border immediately returns to Mexico, often precisely because the prospect of apprehension by Border Patrol agents in the immediate area becomes clear,” DHS said in a statement.

DHS said every metric currently available shows that security efforts are producing significant results.