Transcript for Authorities search for motive behind shooting at doctor’s home
tonight, there was another awful shooting, this one in south Carolina. A doctor, his wife, two of their young grandchildren among the five who were killed in rock hill, South Carolina. And tonight, authorities believe it was a former NFL player who killed them before killing himself. Tonight, we have the family picture of that doctor and wife. They had many grandchildren and you can see the two there behind them who authorities say were victims in this, too. Along with an air conditioning technician who happened to be at the home, they say also killed. There was an hour's long standoff with police and ABC's will reeve tonight in south Carolina. Reporter: Tonight, authorities searching for a motive behind the horrific mass murder in the quiet town of rock hill, South Carolina. Be advised, we've got four down. Four down inside the house. Reporter: A prominent local doctor Robert Lesslie, his wife Barbara and two grandchildren, 9-year-old Adah and 5-year-old Noah, gunned down in their home. Outside, 38-year-old James Lewis, who had been working at the property, also found dead. A coworker seriously wounded. Authorities launching a desperate manhunt -- The description we were given was a black male, wearing black clothing, carrying something red. Possible automatic gun. Reporter: That search would lead them to a former NFL player, Phillip Adams, who was found barricaded inside his parents' home nearby. After an hours long standoff, police entered to find Adams dead of a self-inflicted gunshot wound. Intercepted by Phillip Adams! Reporter: Adams spent five injury-riddled seasons in the NFL, playing for six teams and suffering at least two concussions within a three game period in 2012. He retired in 2015. Adams' father, Alonzo, telling a local station, WCNC, his son never bothered anybody. I can say he's a good kid, he was a good kid, and I think the football messed him up. Reporter: According to reports, Adams may have at one time been a patient of Dr. Lesslie. The fashion's friends and family left in shock by the gruesome killings. He was just an exceptional person. And to see this happen to his family is just tragic beyond words. Reporter: Relatives of the victims releasing a statement today, saying, "We are in the midst of the unimaginable, there are no answers that will satisfy the question 'why.'" so far, investigators unable to answer that question. There's nothing about this right now that makes sense to any of us. Reporter: Beloved in his community, Robert Lesslie founded two local urgent care centers and work gd as an E.R. Doctor for decades. In a 2008 book, titled, "Angels in the E.R.," Lesslie wrote, " know without a doubt that life is fragile." Will reeve with us in south Carolina tonight. I want to go back to that point you made in your report that there are unconfirmed reports that the suspect may have been a patient at some point of the doctor? Reporter: Yes, David. The suspect's father said today that he had been treated himself by Dr. Lesslie years ago. There are also reports that his son, Phillip Adams, had been treated by the doctor, as well. But police here would not confirm that today. That possibility is sure to be explored as they try to determine a motive for these killings. David? Certainly learn more in the hours and days ahead. Will reeve tonight, our thanks to you, as well.
This transcript has been automatically generated and may not be 100% accurate.