In eastern Germany, two old men face each other across a gym. Both are German, sit in wheelchairs and are 100 years old. 

But there the similarities end. One of them is Leon Schwarzbaum, a HolocaustThe murder of six million Jewish people in Europe by Nazi Germany. Members of other minority groups were also killed. survivor. The other, his face hidden behind a blue binder and his name only given as Josef S, was a member of the SSShort for the Schutzstaffel, a paramilitary organisation in Nazi Germany that directly served Hitler and his party..

Josef S, who turns 101 this November, was a guard at Sachsenhausen - a concentration campA large prison for people held without legal justification, such as political prisoners or persecuted minorities. The first concentration camps were built by British colonial rulers in South Africa, but the term is most associated with Nazi camps, some of which were used to execute Jewish and other inmates as well as to imprison them. in which Schwarzbaum's family was imprisoned. He is being charged for "knowingly and willingly" assisting in the murder of 3,518 people.

He is being prosecuted for his contribution to the camp's atrocities, which include using poison gas Zyklon B and executing Soviet prisoners of war by firing squad. He was aged 21 when he joined in 1942. If convicted, he could spend several years in jail.

Josef S is the oldest Nazi crime defendant. He joins a growing line-up of elderly Germans facing criminal charges for acts committed during World War Two.

The first was 89-year old John Demjanjuk, in 2009. At the time, his case was deemed "Germany's last major Nazi-era war crimes trial". Instead, it marked a new era in the hunt for Nazis.

In German law, most crimes have a statute of limitationA law determining the length of time during which legal proceedings against a crime can be taken. Britain, uniquely, has no statute of limitations for crime.. Murder is an exception. Prosecutors argued that as a guard at SobiborOne of six extermination camps, which the Nazis established during World War Two for the sole purpose of murdering over 2.7 people, the majority Jewish. Demjanjuk could be trialed for accessory to murder without evidence of a single specific case.

There have been several high profile cases since. One, 93-year old Johann Rehbogen, had his case dropped after he was found "permanently unfit for trial". Another, 96-year old former camp secretary Irmgard Furchner, had her trial delayed after she attempted to escape her nursing home.

Some argue that something looks wrong: a very old woman driven to distress because of a role she played a lifetime76 is the average lifespan in several countries, including Argentina, Hungary, Mexico and the UAE. ago. Should the choices made by a teenager affect her eight decades later?

Millions similarly complicitTo be involved with others in an unlawful or morally wrong activity.  have died without punishment. Why should those who live to a very old age bear the brunt?

The Nazi regime has been near-universally regarded as evil. Living with the shame of being part of it is punishment.

Nazi hunter Dr. Efraim Zuroff disagrees. He has not seen "a single defendant who... expressed any regret or remorse". We should not be fooled by appearances. Josef S may be frail now, but when he committed the crime he was at the height of his strength.

Time does not heal all wounds. Christoffel Heijer, whose father was a Dutch resistance fighter shot at the camp, is one of 17 co-plaintiffs prosecuting Josef S. He told Berliner Zeitung: "Murder isn't destiny; it's not a crime that can be legally erased by time."

Should there be an age limit to prosecutions?

Yes. The past is a foreign country, and three quarters of a century is a long way away. It is ludicrous to punish a nonagenarian woman for crimes committed when she was barely out of school. We should focus on ensuring that today's youth do not repeat mistakes.

No. The trials of Josef S and other former Nazis is not about punishing a particular old man. They are about raising awareness, so that present generations do not forget the despicable outrages committed. We need to be confronted with our worst.