Examples

投案自首

surrender oneself to the police or judicial department

自首至足

from head to foot

父亲深明大义，送儿子去投案自首。

The father was very principled: he sent his son to give himself up.

自首

投案自首。

The thief restored stolen property when he turned himself into the police.

小偷向警察自首时归还了他偷的东西。