WASHINGTON—According to a study released Friday by the U.S. Census Bureau, more than 12,000 undocumented immigrants currently reside within sections of the border wall that separates the United States and Mexico. “Over the past decade, thousands of individuals from Mexico and Central America have flocked to our nation’s southern border, breached the tall steel barriers, and started building lives for themselves inside the wall,” said the bureau’s associate director for research, Clara Smythe, who added that once immigrants find a space for themselves between the wall’s thick metal plates, they typically bring their extended families to live with them, further exacerbating the problem. “And reversing the flow isn’t as simple as sending people back to their home countries. Our study found that six months after deportation, many of these migrants end up right back inside the wall, often crouching behind the very same fence panels.” Census officials went on to state that individuals with refugee status may be eligible to apply for asylum and permanent residence within the wall.