Anna Kepner Case Complicated by DNA Evidence Questions

The case against Anna Kepner's accused killer is facing new scrutiny ... after newly unsealed court records revealed the suspect's lawyer claims the FBI has no DNA evidence directly tying him to her strangulation.

According to court testimony first highlighted by FOX 35 Orlando, investigators could not say whether any DNA was recovered from injuries on Anna's neck. An FBI agent reportedly said he was unaware of any forensic evidence directly linking Timothy Hudson -- Anna's 16-year-old stepbrother -- to her death.

The issue surfaced during questioning about the government's forensic evidence ... with investigators reportedly acknowledging they could not determine whether the person who allegedly sexually assaulted Anna was also the person who killed her.

Newly unsealed testimony also revealed investigators obtained DNA from a second teenage boy who allegedly had a sexual encounter with Anna during the cruise, though prosecutors say testing still pointed overwhelmingly to Hudson, according to a Fox News report.

As TMZ previously reported, prosecutors allege Hudson raped Anna before strangling her inside their shared cabin and hiding her body beneath a bed. Prosecutors have further alleged Hudson held Anna in a chokehold for several minutes, continuing to squeeze after she lost consciousness in what they described as a "barbaric" killing.