U.S. Border Patrol agents in Texas are seeing a significant spike in sex offenders attempting to illegally cross the border from Mexico into the United States.

Local TV station KRGV found that illegal immigrant sex offenders have been found just about everywhere in the Rio Grande Valley, and agents are finding them more often than in the past, catching 144 of them in just the last five months compared with 93 sex offenders over the same time period last year.

They picked up a woman from El Salvador in December who had been convicted of child sexual assault in 2009 in Dallas County, and three Mexican nationals were caught later that month near Harlingen, according to the KRGV. And in February, seven sex offenders were caught in a variety of places, as well as two Mexican nationals and two Guatemalan citizens.

Sex offenders are often caught trying to sneak through thick brush and try to blend in with other illegal immigrants in order to avoid getting found out.

In order to catch them and distinguish them from other illegal immigrants, Border Patrol agents tap into worldwide criminal databases, and have improved technology for biometrics, which involves facial recognition, fingerprints, retina scans, and more.

Why are sex offenders heading into the United States? Agents aren’t exactly sure, but it’s possible they fear being punished in their home countries.

A recent New York Times report found that 2,059 foreigners who were convicted criminal were arrested during a five-day nationwide operation, including 1,000 who were convicted felons. They were arrested ina  sweep by Immigration and Customs Enforcement. President Obama is trying to win support for his bid to protect millions of illegal immigrations from deportation by cracking down on immigrants who have committed crimes, experts believe.