A Syrian man suspected of planning a bomb attack was checked by a trainee guard 15 minutes before he was found dead in a German jail cell, authorities say.
Jaber Albakr, 22, was suspected of planning an Islamic extremist bombing and killed himself using his T-shirt , the head of the prison where he was held said.
Rolf Jacob told reporters in Dresden that a trainee guard checked on the prisoner at 7.30pm and when he returned at 7.45pm he found Albakr dead.
Saxony's justice minister, Sebastian Gemkow, said the suspect was declared dead a half hour later.
Mr Jacob confirmed reports that Albakr had destroyed a lighting fixture in his cell on Tuesday, but said "it was not interpreted as a suicide attempt". Power to the cell was cut off after that, he said.
He said authorities who assessed Albakr when he entered the prison had noted there was a suicide risk but did not consider it acute.
"This should not have happened even though we did everything we could to prevent it." Mr Gemkow said.
Germany's top security official, Interior Minister Thomas de Maiziere, said Albakr's death would make the investigation into whether he had accomplices in the thwarted plot far more difficult.
"I'm unbelievably shocked and absolutely speechless that something like this could have happened," said Albakr's public defender, Dresden attorney Alexander Huebner.
Wolfgang Bosbach, a senior member of Chancellor Angela Merkel's party and security expert, told n-tv that given his behavior, Albakr should have been under constant observation.
"The suicide danger was known, it was not just an assumption," he said.
Saxony state authorities were already facing criticism after Albakr eluded police as they prepared to raid an apartment where he had been staying in the city of Chemnitz on Saturday.
Inside the apartment police found highly volatile explosives and a homemade bomb vest.
Albakr, who had been granted asylum after coming to Germany last year, was finally arrested on Monday in Leipzig after three fellow Syrians tied him up and alerted police.
He had been granted asylum after coming to Germany last year, and had been under surveillance by German domestic intelligence since last month.
On Wednesday, Mr de Maiziere said that Albakr had undergone a security check last year, but it did not turn up anything suspicious.
"There was a check against security authorities' data in 2015, but without any hits," he said. "It's not clear when he was radicalised."
German authorities have said they believe he had links to the Islamic State group and was thought to be planning to attack a Berlin airport, possibly as soon as this week.
The three Syrians who captured the suspect had been granted asylum and their "behaviour deserves praise and recognition", Mr de Maiziere said.
Authorities have another suspect alleged to have been involved in the plot in custody, identified only as Khalil A, in keeping with German privacy laws.
The 33-year-old Syrian was the tenant of the Chemnitz apartment where police found the hidden explosives and was arrested over the weekend as a co-conspirator.