French authorities are focusing on four people suspected of being involved with an attack that killed four on January 9.

A police officer has been taken into custody suspected of accessing files related to her boyfriend in the days after the attack, ABC reports.

The policewoman’s boyfriend was identified only as Amal or Amar, who was suspected of having supplied weapons to the attacker Amedy Coulibaly.

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Amal was already in jail over drug charges, the ABC reported, raising doubts in French media whether he was part of a criminal or terrorist network.

The Independent newspaper identified the policewoman as “Emmanuelle”, who had converted to Islam two years ago but kept the fact secret. She was suspended from her role in the Gendarmerie in February.

It is suspected she allowed Amal into the high-security headquarters of the Gendarmerie without permission, the newspaper reported.

The attacks on the Hypercacher kosher supermarket on January 9 killed four people and were conducted in coordination with the Charlie Hebdo magazine attacks which killed 12 two days earlier.

Coulibaly killed one policewoman during his attack. He died on the day.

The two others arrested in the police swoop were not identified.

The attack on Charlie Hebdo’s office was conducted by two other gunmen, brothers Cherif and Said Kouachi, who died in a shootout with Police on January 9.