To summarize as succinctly as possible, Byron Case acted quite boorishly towards Anastasia's family.

He knew himself to be a prime suspect in the investigation of her murder; even if he were absolutely innocent of murder, he had an strong stain of suspicion about him, and should have felt a certain responibility to deal with that.

In addition, even if Case's alibi were true, it still means he simply left Anastasia in an area they acknowledged to be a "bad part of town", and made no effort to help her out or alert anyone of her whereabouts for more than an hour. If he wasn't guilty of the murder, he certainly carried the guilt of extreme negligence, and displayed no remorse for those actions.

During the weeks that followed Anastasia's murder, Case wrote to her father and godfather complaining that they had been ill-treating him,¹,2 acting as if he were the victim. A few months after that, Case sent another email complaining that someone had accosted him at a shopping mall, bothering him about his connection to the murder investigation, and even though he refused to identify the person, he drew the immediate conclusion that the family (specifically Anastasia's younger sister) was responsible, and made a direct threat to sue.³ All through this time, Case openly mocked and denigrated Anastasia's relationships with her family and other friends,⁴ acting as if he always had been her closest friend.⁵

While many of Anastasia's friends and family dealt with the issues of what is known as "Survivor Guilt",⁶ Byron Case, as one of the last three individuals known to have seen Anastasia alive, who by his own alibi left her to walk alone in a dangerous and deadly area, and then lost another friend only days later to an apparent suicide, showed no such guilt or remorse. Instead of working with police and trying to show his innocence, he was openly arrogant and uncooperative with them.⁷

Instead of making an effort to remove the horrible odor that surrounded him and his actions on the night of the murder, Byron Case simply disparaged everyone and everything: Anastasia's friends, Anastasia's family, even Anastasia herself.

How did Byron Case behave toward Anastasia's family? He behaved exactly like he believed he was getting away with murder.