Ousted Egyptian President Mohamed Morsi is seen behind bars during his trial at a court in Cairo May 8.

CAIRO — Egypt is investigating jailed ex-president Mohamed Morsi in connection with documents that judicial investigators say were leaked to the Qatar-based Al Jazeera satellite news channel, security sources said on Thursday.

Relations between Qatar, a Gulf Arab state, and Egypt have been tense since mid-2013 when then-army chief Abdel Fattah al-Sisi toppled the Islamist Morsi after mass protests against his rule. Qatar supported Morsi and his Muslim Brotherhood.

Morsi is being questioned in connection with his secretary’s daughter who is suspected of leaking sensitive security documents to Al Jazeera, the security sources said.

“The security officials recorded a phone call between the daughter of Morsi’s secretary and an Egyptian journalist who works for Al Jazeera in which the woman said she wants to give him important security documents,” said a security official.

“Morsi is being investigated to find out if he knew about this phone call or if he had leaked these documents to his secretary,” the official added. “We also know that the woman had been trying to send the documents to the Qatari intelligence.”

The satellite channel said in response: “Any information Al Jazeera receives is handled with the highest standard of journalistic ethics. We do not therefore comment on sources, or pass information to governments.”

Al Jazeera has been banned from Egypt over what Cairo says is its support for the Brotherhood. Al Jazeera says it aims for balanced news coverage airing all points of view.

Sisi went on to become president while Morsi has been jailed on suspicion of inciting violence and various other offenses. He and other Brotherhood leaders could face a life sentence or the death penalty if convicted.