What crime is it to post sensitive photos of others online?

(Baonghean.vn) - According to information provided by Ms. Nguyen Thi Hong N (Anh Son district, Nghe An province): Ms. N loved Mr. Nguyen Van T for three years when she was a student. After graduating, due to many changes in her job, Ms. N and Mr. T broke up. Currently, Ms. N is married to someone else and has a child. On September 24, 2017, Mr. Nguyen Van T sent a message containing sensitive photos of Ms. N via Facebook with a threat: If Ms. N does not transfer 50 million VND to Mr. T within three weeks, he will publicly post Ms. N's nude photos on social networks.

Question: What crime did Nguyen Van T commit?

Trong Hai - Lam Tung