NEW YORK — Last week, the FBI announced the capture of Jose "Joe" Luis Saenz, an alleged gang member and murderer who, since 2009, had been on the FBI's Ten Most Wanted Fugitives list. Saenz was captured in Guadalajara, Mexico, where he had been living above a beauty parlor. According to the Associated Press, Saenz had gone to great lengths to disguise his identity: losing weight, removing tattoos, disfiguring his fingerprints. But it's unclear whether he was able to alter his fat, distinctive baby face.

That baby face may have helped Saenz get on the list in the first place. Ever since the Ten Most Wanted Fugitives list was created in 1950, many have assumed that the list contains the worst of the worst — that it's something like a power ranking for crooks. And, indeed, the list has contained fugitives who've loomed large in the public imagination: Osama bin Laden, James Earl Ray, Whitey Bulger, Eric Rudolph, Ramzi Yousef.

But in a New York Times article this June, Michael S. Schmidt noted that "bureau officials have also tried to select other dangerous fugitives who may have been hiding in plain sight but could be recognized by the public because they have distinctive physical features." In other words, a weird-looking fugitive is more likely to make the list than a criminal without distinctive marks.

This makes sense. The whole point of the list is to motivate the public to help identify fugitives, and it's easier to identify someone whose face is hard to forget. Joe Saenz has the sort of broad cake-eater's face that would stick in your mind if you saw it, and might trigger recognition when you saw that face on a wanted poster.

The FBI issued its first "wanted poster" in 1919, in an effort to catch a runaway soldier named William N. Bishop. (Bishop had four vaccination scars and a "massive lower jaw.") The Most Wanted list was created after a wire service reporter in need of column copy asked the FBI for a list of its 10 worst fugitives. The subsequent story generated enormous positive publicity, and prompted J. Edgar Hoover to institutionalize the format; in 1950, the bureau issued an official list of 10 notorious murderers, kidnappers, escape artists and car thieves. An American legend was born.

The list soon became a valuable publicity tool, a way for the FBI to increase the heat on those criminals who had proven the most elusive, like folk-hero bank robber Willie Sutton and noted cattle rustler Chester Davenport, who was caught two days after being added to the list. (He was arrested while milking a cow; it is unclear whether the cow had tipped anyone off.) Fugitives generally stay on the list until they are caught or confirmed dead. When a spot opens, the FBI field offices nominate potential replacements.

"To get one of your fugitives on the Top Ten list, you were a salesperson," an ex-FBI agent was quoted as saying in The Encyclopedia of the FBI's Ten Most Wanted List. "You had to present this person in the most negative light." In order to make the list, they have to be considered dangerous, elusive, and vulnerable to nationwide publicity. It also helps if they're ugly.

Eric Toth, an alleged child pornographer who took Osama bin Laden's spot on the list earlier this year, is a tall, thin dude with a weirdly shaped head and a distinctive mole under his eye. Rape and murder suspect Fidel Urbina, added to the list on June 5, has acne scars on his right cheek. Alexis Flores, wanted for the abduction, rape, and murder of a five-year-old girl, has scars on his forehead and right cheek. Jason Derek Brown, on the list since 2007, is a suspected robber and murderer who sort of looks like Sean Penn.

These fugitives are dangerous, to be sure, but they're hardly the sort of supervillains a layman might expect to find on the Ten Most Wanted list. Then again, "A Few Notorious Louts and Several Other Dangerous Guys with Visible Scars" doesn't have the same ring to it. Eric Toth is a bad guy, undoubtedly, but it's hard to say that he's worse than Randy Yager, a motorcycle gang leader wanted on racketeering charges involving murder and arson, or Daniel Hiers, an ex-cop wanted for molesting a teenager and murdering his wife. Hiers and Yager are both on the U.S. Marshals' 15 Most Wanted List, a similar rundown containing totally different personnel. Both men are relatively normal looking.

Peters writes Slate's crime blog.