A Syrian man suspected of planning a bomb attack on a German airport was found dead in his cell late Wednesday at a prison in Leipzig, officials have confirmed.
Sebastian Gemkow, minister of justice for the eastern state of Saxony, said he would give further details regarding the suicide of Jaber al-Bakr at a press conference at 11 am (0900 GMT) on Thursday.
Sources told dpa he had been found hanged.
Al-Bakr's defence lawyer Alexander Huebner called his client's death a "scandal of justice," saying that a prison boss had confirmed to him earlier on Wednesday that the 22-year-old was under constant surveillance.
"He had already destroyed lights and fiddled with power points," Huebner told German website Focus Online.
The tabloid Bild said that the Syrian's cell was only checked at intervals of a little under one hour.
Following his death, politicians expressed disbelief that a suspect who was considered a suicide risk had been able to kill himself.
"How can someone, who's supposedly under constant surveillance, be found hanged?" tweeted Greens lawmaker Tobias Lindner.
Al-Bakr, whom investigators said had links to Daesh, was arrested on Monday after a two-day manhunt following the discovery of explosives and other bomb-making equipment at his flat in the city of Chemnitz.
He narrowly avoided arrest on Saturday when his flat was raided, but was later captured and handed over to police by three Syrian refugees who have since been lauded as heroes.
However, sources told dpa that during police interrogation al-Bakr had accused the refugees of having known in advance about the planned attack.
The truth of the accusation was not clear, and prosecutors in Karlsruhe leading the investigation refused to confirm the information or say whether the refugees were being treated as suspects or witnesses.
Hans-Georg Maassen, head of Germany's domestic intelligence agency, earlier this week said it had received a tip last month that Islamic State was planning an attack on German infrastructure.
"In the end the plan became more concrete to attack airports in Berlin," Maassen said.
In an interview published in Thursday's edition of the Frankfurter Allgemeine Zeitung newspaper, he added that al-Bakr would have been ready to carry out the attack within days.
Al-Bakr arrived in Germany as a refugee at the beginning of 2015, but had returned to the Syrian city of Idlib since, according to research by German broadcaster MDR.
It reported that al-Bakr's housemates in the north Saxony town of Eilenburg said that he wasn't very religious, but that he had changed after his return from Syria.
German Interior Minister Thomas de Maiziere confirmed Wednesday that al-Bakr had been investigated in 2015 but that authorities had failed to find anything.
"It is not clear when he started to become radicalized," de Maiziere said.