Destrehan - FBI agents were watching - and recording - when a powerful Louisiana prosecutor arrived at the apartment of a woman facing a drunken driving charge. Bringing two bottles of wine, Harry Morel sat on her couch, discussed her case, and then began to grope her, authorities say.The video of that July 2012 encounter with Danelle Keim would finally help the FBI build a case against the man who served as St Charles Parish's elected district attorney for more than three decades.But as Morel faces sentencing on Wednesday, the evidence also suggests how difficult it can be to balance the scales of justice. Federal and state authorities said Morel solicited sex from at least 20 women in exchange for favourable treatment. They even called him a sexual predator, but he wasn't charged with any sex crimes."So, I'm an important guy?" Morel asked as Keim tried to resist his sexual advances, according to a transcript filed in court."Important? Um, yeah," she said."Well," Morel said, "then I need to order you to kiss me".Important was an understatement for Morel, who had been re-elected five times.According to the FBI and the local sheriff, the 73-year-old prosecutor repeatedly used his power to prey on vulnerable women.But as the patriarch of one of a handful of families with deep connections in politics and law enforcement, he was long considered untouchable in the swampy Louisiana parish, where roughly 50 000 live. FBIThat began to change when Keim dialed 911 and her plea for help reached the FBI."Justice finally came calling for former St Charles Parish District Attorney Harry Morel," US Attorney Kenneth Polite said at an April news conference announcing his guilty plea, to a narrowly tailored charge of obstructing the federal investigation.Morel faces no more than three years in prison.That angers Keim's mother, Tammy Glover, who hopes to address US District Judge Kurt Engelhardt before he issues the sentence. She says Morel should have been charged and convicted of more serious offences."I'm not a physical person at all, but I just want him to hurt," she told The Associated Press in an interview at her home.Still, her disappointment doesn't overshadow her pride in her daughter's courage."She's our hero. She's the hero of S. Charles Parish," Glover said. "She went after the most powerful man in St Charles Parish, and she got his ass."Keim's undercover work would have made her a key government witness. Glover recalls how proud her daughter was in 2013 when she showed her a report in the Times-Picayune newspaper, which revealed that the FBI was investigating whether Morel had been trading leniency for sex with defendants or their relatives."That was my justice," Glover said.Drug addictionLess than 24 hours later, she was dead.The 27-year-old mother of a young son suffered from drug addiction, like most of the women Morel was accused of preying upon. Her overdose was yet another blow to a case that was challenging from the start.Keim had begun wearing a wire for the FBI after making the desperate 911 call to report Morel had sexually assaulted her at her home in April 2010, shortly after her drunken driving arrest."He grabbed me, he kissed me and he touched me in my private areas," she told a dispatcher, her voice trembling. "He wanted me to take off my clothes. He wanted me to take my pants off so he can please me."Keim said Morel left after she pulled away from his kiss - and that she worried it would be "my word against his".The sheriff's office summoned the FBI. It wasn't the first such allegation about Morel to reach the agency.St Charles Parish Sheriff Greg Champagne said he alerted the FBI after he was contacted in 2009 by a woman who claimed Morel told her that her husband's drunken driving charge could be "taken care of" if she would meet him at his camp in Mississippi to "play" while her husband was in jail.DecadesPolite said investigators suspect Morel preyed on women for decades, and he conceded that the full extent of his conduct may never be known."By title, he was the embodiment of justice," Polite said in April. "However, in the darkness of his heart, he was something else entirely - a man who perverted his position of power to take sexual advantage of desperate women who needed help. And he did this over and over and over again."Morel's attorney, Ralph Capitelli, has accused law enforcement officials of engaging in "character assassination" and a "smear campaign" for releasing the 911 call and accusing Morel of conduct for which he hasn't been charged.Morel served as district attorney from 1979 to 2012, and retired after learning of the FBI and sheriff's investigations. At the time, he said he was stepping aside so that his daughter could run for judge free of conflicts of interest.Polite's predecessor had balked at prosecuting Morel, who ultimately admitted to instructing Keim to destroy photographic evidence of their meetings. The plea deal effectively closed both the federal and state investigations, authorities said.Investigators tried to reach all of the women involved, and ultimately determined that the evidence was problematic, Polite said. Many of the cases happened too long ago to be prosecuted under state law. "We had questions about whether the quid pro quo was explicit enough," he said.And many of the witnesses, he suggested, might not be seen as reliable by a jury, given their personal histories.Keim's family said she was a good mother to her son, now 10, and battled through addiction to graduate from drug court and earn her GED. But the pressure of gathering evidence against Morel made her "spiral mentally", said her 27-year-old sister, Tessie Keim."He made her feel like dirt," her sister said. "He targeted these women specifically for who and what they were and where they were in their life."Keim's mother and sister said they have heard from other victims who, despite Morel's guilty plea, remain afraid to tell their stories."If he would have gotten what he deserved, maybe they would have come forward," Glover said.