[centurion316]

By then the Roman Empire was officially Christian

So, more likely the deceased was a member of one of the Christian sects that did not conform to the Council of Nicea.

[Nikas777]

So, more likely the deceased was a member of one of the Christian sects that did not conform to the Council of Nice

Not likely. The Christians preserved the remains of martyrs form the Pagan Roman period and when Constantine came along they built churches in honor of these saints.