Visitors walk through the entrance gate of the Auschwitz concentration camp in Oswiecim, southern Poland, in 2005. Polish police say the sign over the gate was recovered over the weekend in three pieces. (Herbert Knosowski/Associated Press)

Polish police said Monday the five men arrested on Sunday in connection with the theft of the infamous entrance sign from the former Auschwitz death camp appear to have been common criminals.

The original iron sign bearing the Nazi slogan "Arbeit Macht Frei" (German for "Work Shall Set You Free") that spanned the main entrance to the former death camp was located in three pieces in northern Poland on the property of one of the suspects, said chief police investigator Andrzej Rokita.

The sign was stolen early Friday morning from the museum at the site of the former Auschwitz death camp, where over one million people, mostly Jews, were killed or died of starvation and disease while carrying out forced labour at the camp, which the Nazis built in occupied Poland.

Police said none of the suspects have known ties to neo-Nazi or far-right groups.

"They are ordinary thieves," said Rokita.

"Robbery and material gain are considered one of the main possible motives, but whether that was done on someone's order will be determined in the process of the investigation," added deputy investigator Marek Wozniczka.

Suspects could face 10 years in jail

The theft of one of the most chilling symbols of the Holocaust on Friday sparked outrage in Poland and around the world, and police launched an intensive search over the weekend to find the sign.

Wozniczka said the five men, all between the ages of 20 and 39, will be charged with theft of an object of special cultural value and could face up to 10 years in prison. The suspects have not been identified publicly.

Museum guards at the concentration camp memorial alerted police at 5 a.m. local time on Friday after they noticed the sign was missing.

The thieves appeared to have unscrewed the five-metre-long sign on one side and torn it off on the other side, police said. They are believed to have split the sign into three pieces before transporting it out of the town of Oswiecim where the memorial is located.

A replica of the sign — made when restoration work was being done on the original — was immediately hung in place of the missing sign. Non-Jewish Polish inmates made the original sign in Auschwitz in 1940.

The slogan was also used at the entrances to other Nazi death camps during the Holocaust, including Dachau and Sachsenhausen.

Today the site serves as one of the main tourist draws in southern Poland, attracting more than one million visitors per year.

With files from The Associated Press