HOUSTON—The number of dead immigrants found in South Texas has already surpassed last year’s total heading into the two hottest months of 2008.

Since the start of the fiscal year in October, Border Patrol’s Rio Grande Valley sector has found 67 bodies after recovering 61 all of the previous year. The sector runs through the three easternmost counties along the Rio Grande and north along the Gulf of Mexico to almost Victoria.

It is not clear why the deaths are up in the sector. Border Patrol officials point to tougher border security in Arizona, a long string of days with temperatures approaching 100 degrees and smugglers they say don’t care for their human cargo.

“It has already hit 104 (degrees),” said Daniel Doty, a spokesman for the Border Patrol’s sector, said in Friday’s editions of the Houston Chronicle.

“It is generally a three-day walk around the checkpoint, and they are told it is just a few hours,” he said of the Border Patrol’s checkpoints on two northbound highways. “We’ve got these smugglers saying it is a short walk, here is a gallon of water.”

The Border Patrol has a Search Trauma and Rescue Team that focuses on the sector’s most dangerous immigration route through Brooks County.

Immigrants on foot can become disoriented in the heat and vast scrubland north of the border.