The following is the first in a series of articles from an in-depth Associated Press study on deportees who are booted out of the United States and back to their countries of origin.

ORANGE COUNTY, California — Assistant District Attorney Al Valdez says he hears it all the time: “Go ahead, deport me. I’ll be back in two weeks.”

They spit it out as a blood vow, the toughest among them with derisive laughter and expletives added, and many back it up with action, if not in two weeks, eventually.

How many of the criminal deportees eventually make it back to the United States is not known for sure, but estimates from police and researchers start at 40 per cent.

Officials in the home countries of the criminal deportees report the same pattern. In El Salvador, for example, Metropolitan police chief, Eduardo Linares, estimated that 60 per cent or more of the criminal deportees to his country end up returning to the United States.

Much of the evidence is anecdotal, but there are also some intriguing statistics. Testifying before Congress in 1999, Robert Bach, then an associate commissioner of the Immigration and Naturalisation Service, cited a 1997 study of the Los Angeles County jail system. It found 75 per cent of the criminal aliens who had been removed from the county’s jails and deported over the previous six years had not only returned to the United States but were back in county jails again for new offences.

Many deported from Los Angeles are Mexicans who don’t have far to go to get back. The percentage returning from other countries is likely to be lower.

The deportations, authorised by a 1996 federal law, were intended to reduce crime in the United States; but there is no hard evidence that it is working — and many in law enforcement doubt that it has made much of difference.

Even Lamar Smith, a Texas Republican who is one of the primary authors of the law, says the law is not accomplishing as much as he had hoped because of America’s porous borders.

Angel Maturino Resendiz, the congressional poster boy for dangerous, returning criminal deportees, was one who made it back. Repeatedly.

Resendiz was 14 when he first came to the United States from Mexico and 17 when he first got in trouble with the law. Over the next 20 years, he was arrested 16 times, deported at least 8 times, and kept returning, using at least 11 different aliases.

Each time he returned, according to the Justice Department’s Office of Inspector General, he committed at least one new crime — burglaries, car thefts, carrying concealed weapons.

What police did not discover until 1999 is that Resendiz was also killing people — seven in Texas, two in Florida, two in Illinois and one each in California, Kentucky and Georgia, all near the freight train lines he rode from coast to coast. He is now on death row in a Texas prison.