Anna Kepner's Dad Reveals Why He Won't Attend Murder Trial

There won't be a seat saved for Anna Kepner's dad at her upcoming murder trial ... 'cause he says he'll only go if he's forced.

Christopher Kepner revealed he has no plans to attend the trial to watch his stepson, identified as "T.H.", tried for the murder of his daughter, 18-year-old Anna. Anna's 16-year-old stepbrother, T.H., is accused of sexually assaulting and then killing her while they were on a family cruise with Carnival back in November.

Christopher's wife, Shauntel Kepner -- the mother of T.H. -- will also not attend.

He told the Daily Mail ... "Unless they ask for me to be there, neither my wife or I will be attending." He says prosecutors have "everything they need" in terms of evidence and it'll be "too painful to relive it all again."

We covered the horrifying case when the news came out -- Anna's lifeless body was found under a bed in the room she shared with T.H. on Carnival's Horizon ship. Her cause of death was determined to be mechanical asphyxiation.

Chris told the Daily Mail he was one of the first to arrive when Anna was found. He remembered ... "I checked her pulse. I pulled her out from under the bed. I knew my daughter was dead long before the medical examiner got there."

We learned at the time her stepbrother allegedly had a strange infatuation with her ... even climbing on top of her in bed one time.