CAIRO (Reuters) - Egyptian prosecutors are investigating the death of a monk who was from the monastery where a bishop was murdered in July, a case that has rattled the biggest church in the Middle East.

Zenon al-Makari, 45, died while being rushed to hospital after suffering severe stomach pains. He had served as a confessional priest for one of two defrocked monks charged with the murder of the Bishop Epiphanius on July 29, fellow monks said.

A Church spokesman said Zenon had suffered a “sudden health crisis” and prosecutors were investigating the cause of death.

Zenon was one of six monks that Coptic Church authorities had relocated away from the Abu Makar (Saint Macarius) Monastery some 110 km (70 miles) northwest of Cairo, a month after the murder there, on Aug. 25.

Monks at the al-Muhharaq Monastery in Assiut, where Zenon was transferred, said he had been distressed and declined to mix with other monks.

He was on a list of witnesses scheduled to testify in the trial of the two former monks, which opened last week, according to a lawyer involved in the trial and a security source in Beheira province, where the hearing is taking place.

The murder of Bishop Epiphanius had rocked the Church in a country where Christians make up an estimated 10 percent of the 96 million population.

Pope Tawadros immediately ordered a freeze on accepting new monks, a ban on monks leaving monasteries without permission, and a ban on clergy using social media.

Judicial sources said one of the monks accused of the killing, Wael Saad, known by his monastic name Isaiah al-Makari, had confessed during questioning to the murder.

Egyptian media reported this week that Saad, at his first hearing, had denied killing Epiphanius and said he had confessed under pressure.

In a statement last month, the prosecution said Saad had long had differences with his superiors, who had on one occasion investigated him for breaking monastery traditions.

The second monk accused of involvement in the murder, Ramon Rasmi Mansour, threw himself from the monastery roof this month. He has been treated in a Cairo hospital where he has also been questioned, judicial sources told Reuters.

(Corrects month of murder in paragraph 1, says Zenon was confessional priest for one of the charged monks, not two in paragraph 2.)