The decision surprised Alba’s supporters, not to mention the worker himself — who faces a controversial rap over his friend’s death, even though he and his hordes of supporters say the video clearly shows he was acting in self-defense , a bodega representative said. “I don’t understand why [district attorney] he hasn’t charged her,” Francisco Marte of the Bodega Group and Small Business Association said outside Alba’s Hamilton Heights apartment after visiting with the worker Monday. He said the 61-year-old employee and his supporters believe the 32-year-old girlfriend should be jailed for stabbing Alba three times while he was fending off her angry boyfriend. “He was involved in it,” Marte said of the incident. “He’s supposed to be in jail and the $250,000 bond [Alba once faced] it should be on her, not him. He was just defending himself.” However, police sources said prosecutors declined to charge the woman because they believed she was justified in helping her boyfriend while he was being cut. The DA’s office has not charged the girlfriend of the ex-convict killed by bodega worker Jose Alba, even though he stabbed Alba three times. “The DA’s office looked at the tape and they felt she was defending her boyfriend,” an officer familiar with the situation told The Post. “They didn’t feel they needed charges.” But defense attorney and former Bronx district attorney Michael DiCioaro said he’s in Alba’s camp on this one. “I have no idea why it’s not being charged,” Discioarro said. “Her boyfriend was the attacker. It does not protect the attacker. Sources say DA Alvin Bragg’s office has not charged the woman because they believe she was justified in defending her boyfriend.Gabriella Bass “We get a good look at how the system works for the average person,” he said. “Imagine if there was no video. Jose Alba would never be released from Rikers and [Simon’s girlfriend] would testify against him, probably testify against himself.” Alba was working behind the counter at the bodega on July 1 when the woman became enraged after her debit card was repeatedly declined as she tried to buy her 10-year-old daughter a bag of chips. The woman claimed Alba was rude during the failed purchase and ran home to get her 35-year-old boyfriend, Austin Simon. Alba stabbed Austin Simon to death after Simon went behind the bodega counter and attacked Alba. Alec Tabak Simon, a career criminal who served prison time for assaulting a police officer, burst in behind the counter and pushed Alba against the wall — then blocked his exit, the video shows. Cornered, Alba reached for a knife and stabbed Simon five times, fatally wounding him — while apparently being stabbed by the woman himself, wild security footage shows. Cops charged Alba with second-degree murder and weapons possession, and he was held on $250,000 bail until the Manhattan D.A.’s office. Former Bronx District Attorney Michael S. Discioarro said he believes the woman should be charged. The woman later claimed to officers that she never stabbed Alba, despite surveillance footage suggesting otherwise, sources said. She could not be reached for comment. Manhattan prosecutors declined to comment Monday, saying the office does not discuss details of pending criminal cases. Earlier Monday, Alba spoke for the first time since the fatal incident. “I’m very SAD. I didn’t think this would happen,” he said in Spanish. “At that moment I was in shock. I didn’t know what to do and what to say. Asked if he had a message for Simon’s family, he said he was sorry. “I would tell them I didn’t want to do that,” he said. “I ask that they forgive me because I did not mean to do this.” Additional reporting by Elizabeth Rosner