When is surrender by an accused considered voluntary, and constitutive of the mitigating circumstance of voluntary surrender?

A surrender by an offender is considered voluntary when it is spontaneous, indicative of an intent to submit unconditionally to the authorities.

To be mitigating, the surrender must be:
(a) spontaneous, i.e., indicative of acknowledgment of guilt and not for convenience nor conditional;
(b) made before the government incur expenses, time, and effort in tracking down the offender's whereabouts; and
(c) made to a person in authority or the latter's agents.


Related:

Mitigating Circumstances
Aggravating Circumstances
Justifying Circumstances
Alternative Circumstances