Police have arrested a man who is accused of supplying the corrosive acid to José Arcadio D.N. - nicknamed 'El Melillero' - the main suspect in the attack on two young women in Cártama on 12 January.
The Spanish man has appeared in court and been remanded in custody while police investigate whether he played a more significant role in the incident.
At the time of the attack witnesses said two people fled the scene in a grey Volkswagen Golf.
The main suspect in the attack José Arcadio D.N. - nicknamed 'El Melillero' - was arrested after a manhunt that lasted several days and involved several high-speed chases.
Police subsequently uncovered a network of family, friends and acquaintances who allegedly helped 'El Melillero' try to escape arrest.
José Arcadio D.N. is now in custody facing attempted murder charges on his ex-girlfriend Sandra and her friend Cristina. He has also made several court appearances in relation to previous cases that he was already wanted in connection with.
The Guardia Civil continues to investigate the acid attack in 'Operation Tindra' - a combination of the names of the victims - Cristina and Sandra.