BOGOTA (AP) — As Bogota's two-term mayor, Antanas Mockus dressed as a superhero to fight graffiti, soaped up in his skivvies on TV for water conservation and sent mimes into the capital's streets to chastise misbehaving motorists with a smile.

The mathematician and former National University president shuns political machines and has run as a minor candidate for president before. Which is why few took him seriously in the May 30 presidential race — until now.

In only a month, the Green Party candidate has rocketed in opinion polls from single digits into a statistical dead head for the lead in the contest to replace the popular, termed-out President Alvaro Uribe.

More dramatic still: at least one new poll, released late Thursday, shows him likely to win the presidency in a second-round vote on June 20.

Mockus had a 50-44 percent second-round lead over former Defense Minister Juan Manuel Santos in the new poll by the Centro Nacional de Consultoria polling firm. Santos had a statistically insignificant 35-34 lead in the first round, according to the poll commissioned by CM& Television. It had a 3 percentage point margin of error.

Several other candidates ran far behind.

Mockus' sudden ascendancy is all the more surprising because Santos is so closely identified with the hardline policies of Uribe, who made major inroads against leftist rebels in his 2002-2010 tenure — winning him some of the highest presidential approval ratings in Colombian history.

"We're going to win in the first round," Mockus tells an Associated Press reporter, almost in a whisper, as he gazes out the window of his SUV after leaving behind a crush of journalists at a campaign stop.

The son of Lithuanian immigrants, Mockus has assiduously avoided Colombia's traditional, corruption-tainted political parties. His position as an outsider appears to be his advantage.

"The people are tired of politics," says Armando Borrero, a former presidential aide who knew Mockus when both taught at the National University in the 1980s. "Mockus is a refreshing figure who clearly has not stolen money."

He is also running as a team with two other pattern-breaking ex-mayors of Bogota — and has shared some of their popularity.

Enrique Penalosa banned parking on sidewalks, built bike lanes, turned major avenues over to pedestrians and bike riders on Sundays and launched a municipal bus service that has been copied throughout the developing world. Luis Garzon invested in schools, parks and medical clinics in poorer districts.

The two are expected to obtain powerful posts if Mockus becomes president.

To many, Mockus was first known for dropping his trousers and mooning a group of unruly students when he was university president in the early 1990s.

Just this month he caused Colombians' hearts to skip a beat when the 58-year-old revealed that he has early stage Parkinson's Disease, bringing him even more attention.

Doctors say the degenerative disease is slow-moving and shouldn't affect his cognitive powers.

The bespectacled man with the Amish-style beard probably benefits most from accepting the centerpiece of Uribe's tenure: a full-bore military campaign to eradicate the leftist rebel Revolutionary Armed Forces of Colombia, or FARC. Like Uribe, he has refused to seriously entertain a FARC proposal for a prisoner swap.

"I think we've spoiled the FARC, symbolically rewarding it for its kidnappings — or rather, we have allowed it to manipulate us through its kidnappings," Mockus told the AP.

While other candidates have tiptoed around the issue, Mockus says flat out that he has no interest in trading jailed rebels for the 20 police and soldiers the FARC holds prisoner.

Mockus also has fiercely condemned the hundreds of extrajudicial killings allegedly committed by Colombia's military on Uribe's watch.

What puzzles some is Mockus' Green Party affiliation. Environmental regulation — routinely flouted in Colombia — does not appear among his priorities.

"In my opinion Colombia's biggest environmental problem is illegality," Mockus says, blaming deforestation, for example, on illegal drug cultivation. "If we're not able to change the culture, we're not going to address environmental problems."

Skeptics don't believe Mockus is capable of putting the unruly countryside in order. Colombia remains the source of most U.S.-bound cocaine, has the Western Hemisphere's only major leftist insurgency and the largest number of internal refugees after Sudan.

Mockus begs to differ. The man who led this city of 8 million during nonconsecutive mayorships in the 1990s and 2000s calls himself a "clean, tough guy."

So far, none of the other presidential candidates have focused their attacks on Mockus, training their verbal fire at Santos, the front-runner.

The media has been more confrontational, questioning why Mockus waited until he had his party's nomination to announce his Parkinson's diagnosis and criticizing him for addressing issues as a philosopher, rather than a politician.

But even his own camp is surprised by his ascendancy.

"When we started this campaign we were the Three Stooges," Penalosa told the AP. "The press treated us like three crazy guys ... Now, just look at us."


Associated Press Writer Frank Bajak contributed to this report.