When Mary Ann Sherman's son started acting erratically after smoking synthetic marijuana last November, she did what she thought was the right thing: She called police for help.  The Florida mom had no idea her 32-year-old son, Chase Sherman, would end up dead after allegedly being handcuffed and then Tasered multiple times by deputy sheriffs. The deadly incident, which played out in front of his parents' eyes, was caught on police body-camera and dashboard videos, which have been obtained by PEOPLE. The videos, taken on November 20, 2015, show Chase Sherman apparently resisting arrest as shouts of "Stop fighting!" can be heard in the background.  "He's got my Taser!" one sheriff can be heard yelling on the videos.  Even though Chase seemed to give up after a minute and a half, saying at one point, "I quit! I quit!" officers continued to Taser him for minutes. In total, he was Tasered 15 times, the family's attorney, L. Chris Stewart, tells PEOPLE.  Just before he seems to stop breathing, the footage shows him saying, "I'm dead."  Sherman's family watched in horror as police dragged his limp body out of the Jeep Patriot onto the highway. Someone on the footage is heard saying, "He ain't breathing. He ain't breathing!"  The video shows one of the deputy officers say, "Dude, I'm [expletive] fired, man." Someone else responds, "Nah, you're good."  After Chase's body is loaded into the ambulance, two sheriffs are seen high-fiving each other. Chase was taken to a hospital and pronounced dead later that day.  "It's really a tragedy because it's an example of how some officers deal with the mentally ill, which is what this is really about," Stewart, the family's attorney, says.  "They knew he was having a mental breakdown and didn't try to deescalate the situation," says Stewart, who successfully negotiated a $6.5 million settlement for the family of Walter Scott, the man fatally shot from behind in April 2015 by a North Charleston police officer after a daytime traffic stop.  "They actually got Chase cuffed easily, but pulling out Tasers escalated the whole thing," Stewart says.  The Shermans are asking the Coweta County District Attorney to take action. "Their whole world was destroyed," says Stewart. "Chase had never had a criminal record. He was engaged to be married. He helped with the family business. He was the nicest guy on the planet. This is a tragedy."  Coweta County District Attorney Peter Skandalakis tells PEOPLE, "This is a tragic case and it's one we are looking at rather closely. I have been a prosecutor more than 32 years and never encountered this type of situation, given all these facts."  Skandalakis adds, "The first decision we have to make is whether a crime was committed and if a crime was committed, then it would go to a grand jury. But at this point we are still looking at all the facts."  The Georgia Bureau of Investigation, which had completed its investigation in February and sent its findings to the DA, has also reopened the case, says Stewart.  On November 20, 2015, Kevin and Mary Ann Sherman were in the Hartsfield-Jackson Atlanta International airport, on a layover from their oldest son's wedding in the Dominican Republic to their home in Destin, Florida, when Chase began acting strangely, according to police records.  When he refused to board a plane from Atlanta to Florida, the Shermans decided to rent an SUV and drive five hours home.  Chase told his family and his fiancÃ©e, Patti Galloway, he was having a bad reaction to the synthetic drug, Spice. At that point, his mother said the family planned to take him to a doctor when they got home, according to police records. But when the family reached Palmetto, Georgia, Chase began acting erratically in the SUV.  Wanting to get Chase to a hospital, Mary Ann called 911, saying her son "is freaking out" and was "on some kind of drug," according to a statement released by Coweta County District Attorney Peter Skandalakis, who is reviewing the case.  "Chase's parents did what everybody is supposed to do," says Stewart. "You call 911 because it brings help, but in Chase's case, it brought death."  When Coweta County deputies and an EMT responded to the scene, they found Chase "physically combative and would not cooperate in getting out of the back seat," the DA's statement says. It adds, "Multiple attempts were made to subdue Sherman but the Tasers did not seem to have an effect."  The Coweta County Sheriff's Office did not immediately return calls for comment.  CBS News reports that both deputies are still employed with the department, according to Col. James Yarbrough with Coweta County Sheriff's Office. They're identified in incident reports as J.D. Sepanski and S.F. Smith.  In his statement, Skandalakis says, "the review of this case is not complete, the investigation is ongoing and a final decision has not been made concerning the outcome of this case."  Skandalakis's statement adds, "However, in recognition of the great public interest in this matter I have decided to make the body camera and dash board videos available to the media."
The medical examiner ruled Chase Sherman's death a homicide as the district attorney reviews the case and to determine whether to bring it to a grand jury