Prosecutors decided Wednesday not to charge Carmen Reyes Jr. pending further investigation, Ricardo Santiago, a spokesman for the Los Angeles County district attorney's office, said in an email.
Reyes, 58, was arrested on suspicion of murder after the 5 a.m. shooting on Saturday and was released from custody Wednesday. There was no telephone listing for him in Torrance.
Santiago said he didn't know whether Reyes had obtained an attorney.
Sergio Moises Wilms was shot after he walked up to a teenager who was packing a car for a Boy Scout retreat, said something and began hitting him, police said.
The boy's mother heard his screams, ran out of the home and tried to get between the two but couldn't , police Sgt. Robert Watt said.
Reyes, who roomed in the same house as the boy, heard the fight and came outside. He got into some kind of argument or fight with Wilms and "ultimately produced a handgun," shooting Wilms several times, Watt said.
The Scout's name was not immediately released. The teenager was not seriously injured and told police he didn't know Wilms, Watt said.
His mother said that Reyes acted heroically.
"He's a really, really good person to come help," she told the Torrance Daily Breeze ( http://bit.ly/19PeBpW) on Tuesday.
Wilms apparently had been walking in the area for some time before confronting the Boy Scout, Watt said.
"We're trying to figure out the motive (for the assault)," Watt said. "We don't know the frame of mind of Wilms."
Investigators also are trying to determine details of the fatal confrontation with Reyes, who had not given a statement to police.
"We don't know if it was ... excessive on Reyes' end or was it justified because he was in an altercation and maybe fighting for his life," Watt said.
Investigators also were awaiting results of tests to determine whether Wilms might have been drunk or on drugs.
Acquaintances of Wilms said they found it hard to believe that the 19-year-old Gardena man had been violent.
"He was a peaceful kid," said Kathy Patterson, who taught Wilms for two years at a Torrance continuation school.
"He was, like, a throwback to the '60s," she told the Daily Breeze. "He was a hippie and super respectful. He loved to skateboard and had this beautiful long hair. He looked like a Navajo Indian. He didn't like to wear shoes or a shirt."
Wilms had just returned from a farm where he works when he was killed, said Nicholas Xanthis, a longtime friend.
"I've hung out with him every day for 10 years," Xanthis said. "Me and my other friends are crying all day long. He would be the one to stop a fight. He wouldn't be the one to go beat someone. I'm just baffled."
Information from: Daily Breeze, http://www.dailybreeze.com