(CNN) -- The family of a Florida teen who died after being Tasered by police wants answers from authorities in Miami Beach.
Miami Beach police said officers spotted aspiring artist Israel Hernandez spray-painting the side of a vacant McDonald's off Collins Avenue, the city's main drag. Hernandez led them on a foot chase, ignoring commands to stop, until he was cornered, they said.
"In order to affect his arrest, an officer deployed his conducted electrical weapon (TASER)," police said in a prepared statement. But afterward, Hernandez "displayed signs of medical duress" and was taken to a nearby hospital, where he was pronounced dead around 6 a.m. Tuesday.
"We're in a country that defends human rights -- a country that sets an example and dares to ask countries that use excessive force," his father, also named Israel Hernandez, told CNN. "That is my son's case. Excessive force."
Hernandez and his family moved from Colombia to the United States for a safer life. Now they're mourning their 18-year-old son, whose artwork packs their home.
"He was an amazing artist, a very passionate person, a very passionate artist," said his sister, Offir Hernandez. "It's unfair to end his life for something he loved."
Miami Beach police say they have an "open and ongoing investigation" into Hernandez's death and have extended their condolences to the teen's family. Autopsy and toxicology results for Hernandez are pending, the medical examiner's office told CNN.
Police identified the officer who used the Taser as Jorge Mercado, who has been placed on paid administrative leave, which is routine any time a person dies in custody.
"We've never had someone die from a tasing before," a police spokesman said. "We've only had Tasers eight or nine years. Now everyone is issued one when we start working here."
Hernandez tagged buildings under the signature "Reefa." Thiago Souza, a friend who had been acting as a lookout, said police looked "almost like they were proud of what they did" after subduing Hernandez.
"They're all congratulating each other and all that," Souza said. "They were all clapping over his body and like giving high fives and laughing."
Police did not respond to a request from CNN for comment on Souza's account.
"Electronic control devices" like the Taser are now common equipment among police, who say the devices give officers an option short of deadly force to subdue a suspect. Taser International Inc., citing a 2009 study by researchers at the Wake Forest University medical school, says fewer than 1% of those shocked with a Taser or similar device suffer any injury.
A 2006 report by the Florida Department of Law Enforcement concluded that ECDs "are not likely to cause serious injury or loss of life for suspects or law enforcement officers, except in situations where certain medical conditions and drug use are factors." But human rights group Amnesty International says 42 people in the United States died after being shocked with Tasers in 2012, with more than 540 deaths since 2001.
Hernandez is not without critics. Many commenters on Miami news outlets defended the officers, saying Hernandez should have complied with police commands. But Hernandez's girlfriend, who asked to be identified only as "Alexandria," said he was "the farthest thing from a thug."
"He ran because he was scared," she said. "You know, he's just a kid. He only weighed 140 pounds. He was just a child in so many ways. He was such a pure and innocent person."
™ & © 2013 Cable News Network, Inc., a Time Warner Company. All rights reserved.