U.N. human envoy to Burma, Paulo Sergio Pinheiro visited on Monday a prison and a few other sites in order to determine how many people were killed and imprisoned in the September crackdown, Time reports.

This is his first visit to Burma in four years after he was banned to visit the country.

Pinheiro spent two hours at the Insein prison in Rangoon where many political prisoners have been held over the years. Details of his visit here were unknown, but a diplomat said that he would try to visit Min Ko Naing and Ko Ko Gyi, the leaders of the protests held in August regarding fuel price, that are believed to be imprisoned at Insein, Reuters reports.

The statement released by the U.N. office in Rangoon said: “He is expecting to interview detainees before the end of his mission and receive further details on their records.”

On Tuesday the U.N. envoy was invited in Naypyitaw to meet with Cabinet ministers, according to a government official. This meeting is a part of Pinheiro’s probe.

He is expected to hold meetings with officials like the foreign minister, the labor minister and the minister of home affairs.

Pinheiro said that he will gain access to jails and the other sites where allegation of abuse have been made.

In March 2003 he shortened his visit to Burma after a listening device was found in a prison room where he was interviewing one political imprisoned. In that year he also accused the junta for holding in jail political opponents under false pretenses. Ever since then he has been banned from the country.

Government Technical Institute was another site visited by the U.N. envoy “where he met with the personnel in charge of the detainees held there during the days of the demonstrations,” according to the official statement.

The institute served as a temporary detention center for holding the people detained on September. Another detention center was the headquarters of a police regiment in Thanlyin, also visited by Pinheiro.

Two monasteries were also visited by Pinheiro. The monasteries were involved in the protests that took place in September and October, and were led by Buddhist monks.

He also met with senior abbots of the State Sangha Maha Nayaka Committee.

He is expected to leave the country on Thursday.