On Wednesday, the now 81-year-old was in court for the trial of 93-year-old Oskar Groening — charged as an accessory to the murder of 300,000 people at Auschwitz. "Did you know Josef Mengele?" The charges against the former guard relate to a period between May and July 1944 when about 425,000 Jews from Hungary were taken to the Auschwitz-Birkenau complex in Nazi-occupied Poland. Her parents and two elder sisters were taken straight to the gas chambers, while she and her twin sister, both 10 at the time, were used in experiments conducted by Nazi doctor Josef Mengele. Auschwitz-Birkenau death camp 
 
 Image copyright AFP 
 
 Construction began in 1940 on site that grew to 40 sq km (15 sq miles) 
 
 About one million Jews were killed at the camp 
 
 Other victims included Roma (Gypsies), disabled people, homosexuals, dissidents, non-Jewish Poles and Soviet prisoners 
 
 Auschwitz 'may turn away visitors' 
 
 How the Holocaust unfolded, year by year 
 
 Why did ordinary people commit atrocities in the Holocaust?
– A former Auschwitz guard being tried on 300,000 counts of accessory to murder has testified that it was clear to him Jews were not expected to leave the camp in Nazi-occupied Poland alive. "I couldn't imagine that" happening, former SS Sgt. Oskar Groening told the Lueneburg state court today during the third day of his trial, the dpa news agency reported. Groening earlier described a veritable traffic jam of trains arriving at the Nazi death camp, reports the BBC. "For the sake of order we waited until train one was entirely processed and finished," Groening testified; that processing involved marching most passengers directly into the gas chambers. The charges against him span from a May-to-July period of 1944 in which some 425,000 Hungarian Jews were sent to Auschwitz. Most were immediately killed. "Someone said that 5,000 people were processed in 24 hours but I didn't verify this," he said. "I didn't know." The 93-year-old's testimony came in response to questions from attorneys representing Auschwitz survivors who have joined the trial as co-plaintiffs, as allowed under German law. Yesterday saw testimony from Eva Kor, now 81, who arrived at Auschwitz as a 10-year-old. As a twin, she was experimented on by Dr. Josef Mengele, reports NBC News. "On alternate days—Tuesdays, Thursdays and Saturdays—[she and sister Miriam] were brought to a lab. ... They took blood from my left arm and gave me at least five injections into my right arm. Those were the deadly ones." NBC reports Groening was expressionless throughout her testimony. He faces three to 15 years in prison if found guilty.