PARIS (Reuters) - Two men arrested over the murder of a Holocaust-era survivor who was repeatedly stabbed in her Paris home are suspected of killing her because she was Jewish, a judicial source said on Tuesday.

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Mireille Knoll, 85, was found dead with 11 stab wounds at her apartment in a working class area of the capital on Friday. The apartment was set on fire after the attack.

One of the suspects was a long-time neighbor who recently finished a jail sentence for a sex offense, the victim’s son Daniel Knoll told i24 News, an Israeli channel.

He said the neighbor had spent much of Friday, when the Jewish day of rest begins at sundown, chatting with his mother at the apartment, with the two sharing a drink.

According to the judicial source, the arrested men were notified by a judge that they are suspected of murder motivated by the victim’s “real or supposed adherence to a religion”, as well as aggravated theft and damage to property.

President Emmanuel Macron described the death as a horrific crime. “I reaffirm my total determination in fighting anti-Semitism,” he wrote on Twitter late on Monday.

Interior Minister Gerard Collomb said the murder underscored how far France still had to go to combat anti-Semitism. “Since the start of the year, no fewer than 33 anti-Semitic acts have been committed,” he told the Senate. “This cancer cannot be allowed to eat away at our nation.”

Mireille Knoll had lived in the neighborhood - in the building where she died and another on the same street - for 60 years, said Francis Kalifat, head of Crif, a body that represents France’s 400,000-strong Jewish community.

Knoll - who narrowly escaped being rounded up with around 13,000 Jews who were held at a cycling track in Paris in July 1942 before being deported to Auschwitz - had known the suspect since he was seven years old, he added.

One source close to the investigation told Reuters the two arrested men had given conflicting accounts to police. One told interrogators he heard the other shout the words “God is greatest” in Arabic during the attack.

The second suspect is a homeless man, according to Gilles-William Goldnadel, the victim’s lawyer.

Daniel Knoll said his mother suffered from Parkinson’s disease and was not aware that her neighbor had spent time in jail for molesting the 12-year-old daughter of a woman who acted as her live-in carer.

France’s Jewish community, the largest in Europe, has complained for years of a rise in anti-Semitic hate crimes.

In 2015, vandals desecrated 250 tombstones in a Jewish cemetery in eastern France only days after four Jews were killed in an attack on a kosher grocery in Paris.

Knoll’s killing took place a year to the day after the murder of Sarah Halimi-Attal, a 65-year-old whose killing prosecutors believe was anti-Semitic.

France’s chief rabbi on Monday described Knoll’s death as a “horror” and Jewish leaders called for a march in her memory, which is set to take place on Wednesday evening.